Larian Studios Forums Baldur's Gate III Baldur's Gate III - Story & Character Discussion My Pitch for Revamping the Emperor's Storyline (Many spoilers)

I'll start by saying that I like some of the archetypes the Emperor draws from and enjoyed some individual moments with them, but on the whole, I was a bit disappointed.
As it stands, the Emperor really feels like the product of a couple interesting character ideas that were spliced together at a later stage of writing and didn't have time to be fully fleshed out and explored. I've read enough to know that the Dream Guardian was initially a very different character, in personality at the very least, and the sudden switch to presenting themselves as the Emperor in Act 3 currently seems jarring. In Act 3, the character seems to have low reactivity to any previous interactions you've had with them, and no real character arc or branches in the way that your party companions do, despite being a character that has been with you since the start of the game in one form or another. They also have almost no chances to have any meaningful impact on how the story unfolds, which might be partly because of old concepts about who the character was and what powers they might have, and partly because you're stuck with them and there's a fine balance to strike between letting an NPC impact the story without stepping on the player's agency.
A number of characters in the game, like Raphael, express the idea that the party is expected to dislike the Emperor and to see him as being manipulative and abusive. On the other hand, there is a romance path with this character, as well as a number of scenes deliberately designed to make him seem sympathetic. While each player will obviously have their own feelings about the character, this setup makes me feel like the game itself should have some sort of branching path -- so that those who want to rebel against their manipulator getting a satisfying confrontation with him, but also so that those who sympathized with this character and wanted to reach out to him feel like they got a satisfying story, too.
Personally, I would enjoy both storylines. I would enjoy overthrowing a controlling villain who's been interfering with my team. I would enjoy building a friendship with a former hero struggling with the loss of their humanity. What I don't enjoy is a story that straddles the two, seemingly never committing to whether this was a villain or an antihero, and ultimately making it feel like nothing meaningful occurred. My suggestions are going to be aimed at fleshing out these paths, with the payoff during the final interactions between the Emperor and Orpheus.
While I also have criticisms about how Orpheus seemingly came out of nowhere in this plot, I'm not going to be addressing that, frankly. We'll take it as a given that he's trapped in the Astral Prism, that the hammer is needed to free him, and that the need to bring Orpheus's power out of the Astral Prism to fight the Netherbrain is required. I want to keep my suggested changes as close to the existing framework as possible.

Some of these are changes, some of these are merely me stating my interpretations of what information I've found on the character.

First, I don't think that the Emperor should be Balduran. I don't think that this adds anything to the character, and I believe it actually detracts from the "I was an adventurer, just like you" presentation that was initially given. I don't know that the Emperor delivers on feeling like someone whose footsteps the player might be following, but I do know that as soon as the Emperor is revealed to be Balduran, the identity of "founder of Baldur's Gate" completely usurps any other concept of who this character was pre-illithid, and it adds nothing. Balduran is not significant to the story of BG3, and finding out that he became an illithid after his final voyage does nothing good to Balduran's own story. I think the Emperor should simply be an unnamed adventurer whose original appearance is the one we see as the Dream Visitor.
*As a note, I would personally try to find some other name for this character other than the Emperor, to reflect the genderless illithid and player-designed original form of the character. But that's minor, and it is a nickname, anyway.

Regarding their pre-illithid life, I would make the Emperor be an adventurer who had been exploring around Moonrise. Depending on how much time and thought can be spared for it, I would also be tempted to have aspects of the Emperor's early life mirror that of the player character -- for example, their Class and Background details. If the player was a Guild Artisan, the Emperor may mention having worked as an artisan; if the player was a Soldier, they may mention having previously been a soldier, etc. Their story is that were captured by mindflayers and infected. Their party attempted to rescue them and escape the colony. Their party did not survive the ordeal, but the Emperor continued trying to make their way back to Baldur's Gate, eventually transforming before they could make it home. However, miles from the colony, they were outside the influence of the elder brain -- an independent mindflayer. Rather than turn back, they chose to continue to Baldur's Gate.

Now that the Emperor is an illithid, we return to the existing backstory of the character. While trying to figure out what to do with themselves, they began feeding on criminals, which eventually put them on the path to collide with Duke Stelmane and the Knights of the Shield. I imagine that the Emperor happened to kill some of Stelmane's enemies, or perhaps to end up in combat with them, leading to these two finding themselves on the same side. The Emperor's primary interest at the time was self-preservation and perhaps starting to accumulate wealth and security, while Stelmane saw the opportunity in having a mindflayer as one of her enforcers, especially once that seemed somewhat inclined to be reasonable. The two initially got along well, with the Emperor's position in the Knights of the Shield rising as they advised Stelmane and learned to control psychic powers, allowing them to mask their appearance and manipulate others.
This is when Gortash and his ambitions enter the picture. His operation is becoming a threat to the Knights of the Shield. The Emperor and Stelmane start to have arguments about how to deal with it. The Emperor, prioritizing their own survival over all else, advocated for harsher measures. Perhaps it was excessive use of their psychic influence on others. Perhaps it put too many innocents in harm's way for Stelmane's tastes. Whatever the case, she refused. Frustrated, the Emperor decided to use their psychic powers to take control of Stelmane and do what they thought needed to be done for the sake of the Knights of the Shield, intending to release her afterwards. But in the struggle, Stelmane's mind was permanently damaged, and there was no taking that back. The Emperor then found themselves alone and in control, just in time to be defeated by Gortash.
How exactly Gortash managed this isn't clear. It seems that he picked up on the fact that the Emperor was a mindflayer from their use of their powers on their clients, but not how he managed to outmaneuver the Emperor. I have no specific ideas to put forward for that, but I think it could be an interesting point to develop about how Gortash himself operates.

When talking to the Dream Visitor, we can sometimes see glimpses of their vague battle inside the Astral Prism. Currently, this is against githyanki trying to free Orpheus, but unless more is done to flesh out Orpheus's role in the main story, I'd be inclined to change this.
The Emperor is engaged in a psychic battle with the Absolute. This is also the basis for why the Emperor keeps pushing the player to consume tadpoles -- in order to assist them with this battle, the player must have greater psychic powers of their own, which none of the party have developed. The Emperor is hoping to improve their own survival chances by having someone else to support them in this effort, especially since the Emperor's attention is currently divided between Orpheus and the Absolute.
(It may be possible to have a similar effect if the Emperor is simply struggling to psychically restrain all the githyanki that they are dealing with, although they obviously wouldn't say that out loud).
I personally had a pet idea of making it so that lacking the Emperor's protection, or lapses in their protection, would result in the party being "ambushed" during their long rests -- these battles take place in the dream world, but they force the party to expend spell slots, health, etc. to symbolize the struggle of resisting the Absolute. However, with a tadpole'd party member and the Emperor in good health, these events become less likely to occur. (Think of the chance of being ambushed by random enemies when camping away from inns in older games -- it's simply a chance to have a rest interrupted, not that unheard of in D&D tradition).

Now we're getting into the idea I put forward in the earlier Emps and Orphs thread. Mainly, the Emperor's arc hinges on the idea of whether they trust the party (and respect the party's decision-making) or whether they distrust the party (and are inclined to try to manipulate and assert control over them). Our themes here are basically trust, control, and leadership, which I believe fit with the narrative the game has presented.

As a general background for this section, I found that one of the most compelling interactions I had regarding the Emperor was during Jaheira's quest to rescue Minsc. Jaheira wanted to save Minsc by knocking him out, and I put in the effort to make sure to keep him alive. But the Emperor nearly refused to extend the Astral Prism's protection to Minsc, requiring multiple rounds of advocating for it by both the player character and Jaheira threatening to throw the Emperor into a volcano. And the fact that there was an actual possibility of not persuading him here (by choosing to concede) made it one of the few times that it felt like the Emperor's threats had any teeth to it (I'll talk about this more re:Orphic Hammer). I'd like to see more interactions like that, though not always as extreme.

Throughout the game, I would have the Emperor do a mix of two things:
1) Advise the player on how to run their party and discussing the subject with them
2) Meddle with the party's course of action, effectively challenging the player's control of their party

The intent here is not quite to actually be a serious threat to the player's choices, but to give the illusion of a threat, and to make the METHOD of exerting control over your own party be an important part of the Trust/Distrust dichotomy. The debate with the Emperor is essentially that of how to lead and direct your party -- the Emperor advocates for manipulation and overriding the agency of others, while you can choose to advocate for diplomacy, respect, and compassion; but how you treat the Emperor is an important part of that, as well -- you don't get to try to preach about listening to others but then constantly take the Intimidation path with the Emperor himself without it leading to a fight later on. Where the Emperor falls on the Trust / Distrust spectrum is the product of the player's own "leadership style" -- either a hard-earned ally, or an enemy of their own making.

Generally speaking, earning the Emperor's trust comes from dialogue choices that show an open-mind towards mindflayers, acknowledge the Emperor's desire for safety, and can appeal to logic rather than morality. Losing the Emperor's trust comes from options that resolve disputes with them via intimidation or force.
For example, when discussing the Orphic Hammer:
- Trust-path solutions might include reassuring the Emperor that the player does not see freeing Orpheus and killing the Emperor as intrinsically linked (attentive the Emperor's concerns); or pushing for the pragmatic idea that having the hammer around may be useful later and shouldn't be ignored just because it makes the Emperor nervous (logic-based)
- Distrust-path solutions would be based on simply telling the Emperor that since they're dependent on the party, they have to go along with this (intimidation); or options that involve resisting the Emperor's psychic attempts to interfere (by force)
I'd also like to note that submitting to the Emperor's demands every time a conflict arises is NOT the same as choosing the "Trust" path -- this is not about whether the Emperor likes the action you're taking, but whether you're challenging his mindset about how a party should be run. I'd probably make most options that concede to the Emperor simply be neutral; he has not changed his opinions in any way.

While I don't know the exact mechanics of what's going on in the Astral Prism, I am going to say that the Emperor can exert their own psychic influence over anyone in the range of their protection, meaning that they can meddle with nearby NPCs, although they are subject to the party carrying them around. This is to give them some ability to back up their threats, as well as possibly offering some tangible assistance in certain scenarios. In most cases where the Emperor is going to interfere, I would attach a short dialogue with them (as seen in the case where they talk to you after Raphael proposes his deal) that can either persuade them not to interfere (or to be helpful), or call them out on having done so.
For examples of behavior they might demonstrate:
- Manipulating NPCs to avoid answering certain questions, such as if the player tries to talk about the Astral Prism or Dream Visitor to NPCs who have no business knowing (for example, trying to bring it up to druids at the grove, anyone at the goblin camp, etc). These might be unavoidable, but the player has the chance to yell at the Dream Visitor over it
- Alternatively, forcing the player to make saving throws in order to speak of certain things, like when telling the githyanki about having the astral prism (these can be the weak DC 5 checks; the point is just to create the feeling of interference)
- Manipulating the actions of anyone in their range, and not just those branded by the Absolute. This can be a chance for the Dream Visitor to show their support of certain courses of actions by manipulating guards, etc. to allow the players to proceed more easily.
- Threatening to expel companions from their protection

Act 1 -- Opinions and Advice
Although the Emperor may not be willing to break with the party over their decisions, they should still have more opinions about how the party decides to resolve various quests, and rather than just saying lines that the player can't respond to, I would like to see some actual discussions here.
The pattern I would like is for the Emperor to talk to the player before a major decision is made, both offering the Emperor's preferred path and then asking the player to state their intended path. The Emperor need not interfere just because they disagree, especially early on. But then after the decision is made, I would also like to see the Emperor comment on whether the player did as they said they would do, and whether they stand by that decision. And I see no reason to have the awkward delay waiting for long rest dream sequences with the character for all of these; they clearly demonstrate the ability to communicate telepathically whenever they please in later acts.
For example, if a player chose to defend the Grove and had said they were interested in protecting people, the Emperor may comment on how many goblins had to be killed in that fight, and whether this bothers the player.
The companion quests may also be the subject of conversation -- particular in Act 1, I think the Emperor could comment to the player character about the company they keep, rather than talking to any of the companions directly (saving that for later). The Emperor should voice their suspicions about every party member, generally warning the player to watch their back and make sure to keep everyone in line, and other advice one might imagine a manipulative sociopath giving when it comes to controlling their minions. Effectively, the Emperor is trying to use the player as their proxy, since they cannot lead the party themselves (they may even cite anecdotes from their former adventuring party as part of their advice). Not all of their commentary needs to be wrong -- particularly when it comes to knowing each companion's motivations and insecurities, I would expect the mindflayer to be spot on, just in an exploitative way.

Act 2 -- Tempting the Party Members
Playing off the way the Dream Visitor is presented as trying to tempt us to take power, I think I'd like to see cases of the Emperor talking to other companions and providing discussions and debates for the player to weigh in on (loosely echoing some of the intentions with Daisy, I think). I think Act 2 would be a prime location for some of these, as the story otherwise feels a bit narrow, and the feeling of one of your main conversation partners being the voice in your head would fit nicely with that while still fleshing things out a bit more. I would aim for the Emperor to encourage the "ascension" path when available, but keeping the Emperor's own personal interests in mind, too. Some ideas:
- After Gale receives the visit from Elminster, Gale can be seen talking to the Emperor. The Emperor is discussing Netherese magic with him and suggesting the idea that perhaps there are other ways to harness the orb's power other than simply blowing up (with hints towards Gale potentially taking the crown later)
- The Emperor may encourage the player character to help Astarion ascend, as a Vampire Ascendant would be a useful pawn against the elder brain (Astarion currently comes up with this notion himself, but I wouldn't mind some tweaking so that the Emperor is the one who suggests it, and for Astarion to be a little hesitant but very tempted by the idea)
- The Emperor may be in favor of Wyll maintaining his pact to secure the power he has from Mizora (or if the timing were slightly different, to become a political challenger to Gortash)
-The Emperor may try to dissuade Lae'zel from looking for Orpheus, perhaps trying to convince her that this is all a trap set by Vlaakith to lure dissenters into chasing for a dead prince. This may even spark a little quest to find some proof that Orpheus is alive, like encountering a member of his honor guard who's looking for help (and for the Emperor to try to convince the party that this is a spy sent by Vlaakith).
- The Emperor may talk to Shadowheart about her missing memories, offering to unlock some of them, in the interest of trying to pry into her quest (maybe replacing the Noblestalk interaction)

Act 3 -- Start
To kick things off, I would tweak the first major encounter with the Emperor slightly.

Currently, when we arrive in the Astral Prism and see the fight, the Emperor is on the ground, begging us not to kill him, and trying to persuade us that he is our protector. We then have a frankly puzzling amount of time to sit there questioning him, which he patiently endures, WHILE THE FIGHT IS STILL HAPPENING. This, I think, is a horribly missed opportunity for a far more interesting introduction to this character, one which could do a much better job of creating tension between the player and the Emperor (for both those who want to befriend the character and those that want to kill him), as well as one that just... doesn't involve a weird pause in what is supposed to be an active fight.

When you catch up to him in the Astral Prism, the Emperor is clearly in a hard-pressed fight, but he's not on the ground. Perhaps you even see a glimpse of him in Dream Visitor form before having the illusion broken, due to the effort of fighting.
Upon seeing you, his reaction is along the lines of "Finally! Now help me defeat these enemies!"
Based on my personaly experience in this encounter, I think the reaction of the majority of players is neither to immediately attack the Emperor, nor to immediately assist him, but instead more like "WTF is going on here?!" And this is where I think the major shift should be.
The Emperor has no patience for your questions right now. I'd give the player perhaps one simple question they can ask ("Dream Visitor, is that you???" / "Yes! I'll explain later, now fight!"), and if the player hesitates any longer than that the Emperor will mind-control your entire party and use them to finish the fight.
Now, you may protest that this is a horrible breach of player agency in this scene, but... the game is going to railroad you into working with the Emperor regardless. Why not use this as an opportunity to establish the Emperor's "villainous" side and his willingness to do whatever it takes to ensure his own survival? Far more fitting for the character than simply begging for his life, I think.
After the fight is finished, the Emperor will then release his control over your party, and he will now act a bit conciliatory. He'll cite to the urgency of the crisis as his reason for acting as he did, and he will now be ready to hear out your questions and concerns in a calm manner -- this behavior is not to be mistaken for saying that the Emperor is really a good person, but rather showing how much he values being "in control" of the situation; he'll entertain your questions only when he's certain of his own safety.
Here, players who really want to attack the Emperor will get another chance to. This time, the Emperor is a bit tired from the previous attempt to mind control you (he cannot maintin this long-term), but he will try again. He'll make all the arguments he can about how Orpheus will not protect you, as well as just pleading with you to cooperate willingly. If you continue to refuse, you'll get the game-over. It can be open to interpretation whether he broke your mind a la Stelmane, or if all of you were overwhelmed by the Absolute in the chaos. This shift is designed to point the player's frustration where it belongs -- not at Orpheus for not protecting you, but at the Emperor, the character you've actually been interacting with throughout the game. No one who takes this route is going to be happy about "being forced to submit," but that frustration will later be vindicated in the boss fight with the Emperor, assuming that they stick to the Distrust path; that's the real point here.
Otherwise, I think the common path will be that players will first hesitate, and then hear the Emperor out, and then be very uneasy about the whole situation without quite knowing how to act yet. They do need the Emperor's protection, after all, but they'll probably want to get away from this guy once the opportunity presents itself.
Basically, this whole encounter is designed to demonstrate that the Emperor is clearly willing to usurp control of your party from you and use you as his pawns, but he doesn't necessarily mean your party any harm -- at least not while you all have an enemy in common. I believe that is the correct effect to aim for (based on how characters talk about the situation).

Act 3 -- Clashing with the Party
I'd look for some opportunities for the party members to now be in heated arguments with the Emperor for various reasons, some of which could result in the Emperor threatening to expel the party member from their protection if they don't comply. For some alternatives, the party could be trying to convince the Emperor to assist with their own plans and be annoyed that he isn't cooperative (for those who aren't as inclined to be hostile towards him). These could be tied to their personal quests or alluding to the party's offscreen attempts to further the main quests.
Some examples:
- Lae'zel trying to develop a way to open the astral prism by force and angering the Emperor
- Wyll commenting that he was trying to gather information in the city, and the Emperor interfered by manipulating NPCs to hide information (alluding to Stelmane / the Emperor covering his own tracks)
- Astarion trying to get the Emperor to mind-control some people for him to help him find more information about what Cazador's been doing (or trying to learn how to take control of the ritual)
What stance the Emperor is taking on their personal quests / what they're arguing over will have to be reconciled with whatever the Emperor is encouraging them to do in Act 2; it obviously wouldn't make sense for him to interfere with doing the exact thing he was suggesting that they do. These are just loose ideas.

Act 3 -- Orphic Hammer Questline
This was the questline where I had the most specific ideas for ways the Emperor could meddle with you, for obvious reasons. It's the one he has the most personal stake in and the clearest stances on. If the Stelmane quest were more central, I'd say that would be a prime spot to focus on, as well.
My experience with this quest was that the first time I did it, I did not take Raphael's deal but stole the hammer later. The Emperor confronted me about it, and I was curious how harshly he might respond, but my character had expressed an almost naive level of "It's not right to keep Orpheus imprisoned, but I don't actually have a plan," and the Emperor laughed it off, which seemed fair enough.
In my second playthrough, though, I wanted to test some of the dialogue options a little more. I took Raphael's deal (which seems like a terrible idea, frankly), then attempted to lie to the Emperor about it, failed at hiding it from him, and then braced myself to see what the Emperor would now do.
Nothing. He did nothing. Because he can't. He has nothing he can do to back up his threats against us. This is one of the main reasons I just cannot get behind the feeling that he's such a threatening villain. He complains, but he can't hurt us.
Here's my idea for how this quest line plays out:
- The Emperor, as he does now, tries to find out what Raphael offered the players. If they refuse, things can stay basically the same. If they accept, the Emperor will act oddly calm. He'll be very disapproving, but he makes no comment about his future courses of action.
- Let's say the party refused the deal (because this is the one I'm familiar with). They'll then try to go to the House of Hope to steal the hammer. If the Emperor knows what the deal that was offered was, then he can put two and two together and knows what the player is intending to do in the Hells. Before opening the portal, this sparks a dialogue with the Emperor. The player can try to convince the Emperor to allow them to take the hammer, for various reasons. If they succeed, he'll back off. If they fail, then they have to make a saving throw against the Emperor; if they fail the saving throw, he briefly mind-controls them and destroys the ritual components, preventing them from opening the portal (but they can still go accept Raphael's deal if they really want the hammer).
- If the Emperor did not know about the deal before the players entered the House of Hope, he comments on them having the hammer upon their return. Again, there's a chance to converse with him and attempt to convince him to go along with this. If they fail, he simply expresses disapproval.
- If the Emperor is still not convinced, then on a later long rest, the player wakes to find Lae'zel (if available) wrestling with an NPC who's trying to make off with the hammer. The NPC is a random people who's being mind-controlled by the Emperor in an attempt to hide / throw away the hammer so that the party cannot use it. There's one final chance to potentially debate with him about it, although no matter what, the Emperor is forced to yield here -- the hammer is too secure for him to get rid of it.
- For one option on the Trust path, at any point during the conversations with the Emperor about the hammer, the player can offer to let the Emperor be the one to keep the hammer, telling him it's just in case of emergencies down the line. This will make things a little harder if the player later ends up fighting him, but it'll be an easier way to get the path to convince the Emperor and Orpheus to work together.

Also, throughout this process, the Emperor's behavior should be influenced by where he currently stands on the Trust/Distrust (Approval) meter, and perhaps whether his personal quest has been resolved. If the Emperor has already been pushed heavily towards the side of Trust, then he should stop being so inclined to meddle. The DC of the various skill checks against him can also be adjusted based on where he currently stands, making it easier to talk him down the more often you take the diplomatic approach.

Alongside some mix of the above, I would have the quest to investigate Stelmane's murder be a little more involved, as well as remixing the basement exploration. Rather than just showing up with her name on a list of cult murders (with no motive other than "Bhaal said to" given, apparently), I'd want there to be more investigation on why exactly she, and perhaps some of the other names, were on that list. This thread would be a way to explore what Gortash and Orin were up to in the city and how they rose to power, as well as how Stelmane and others were trying and failing to stop them.
As said before, the Emperor was there for this phase of the story, and this would also be a chance for him to reflect on how things went between him and Stelmane, as well as with the other people involved in the story, whom he likely met as part of trying to thwart Gortash.
The player can guide the Emperor in what conclusions he draws from these events, which will heavily influence where he stands on the Trust / Distrust path. If he's convinced that it would have been better to have more faith in his allies and that his paranoid and manipulative tendencies sabotaged his own efforts by straining his alliances, then he'll lean towards Trust. If he's convinced that he should have been even more controlling to leave no openings for Gortash to exploit, then he'll lean towards Distrust.
If possible, I'd love to see this blended in with a more cohesive main plot connecting the events of Act 3 and related to resolving the Orin/Gortash phase of the storyline.

This is slightly going off-topic, but I really wish that the Emperor weren't so overtly interested in sex with the player. It feels incredibly strange coming from a mind-flayer, and this character seemed like one who'd be a good candidate for a character the player would have to be the one to express sexual interest in. There can still be a quiet scene of the Emperor expressing that they've come to enjoy the player's company and possibly even reflecting on missing their days of working with their party, but I think it should be up to the player to express romantic interest in the Emperor, which the Emperor can go along with after expressing some confusion.

Also, I feel like the ability to romance this character should probably be exclusive to the Trust path (i.e. not a player who's constantly telling the Emperor how much they hate him / mind-flayers), and some other conversation can occur here on the Distrust path -- still on the subject of companionship, but with a different tone. For example, for the Emperor to remark that he knows that neither of you are happy about the current arrangement, but trying to encourage you to stay focused on your mutual goal of beating the Netherbrain and then going your separate ways. This seems like a good way for the scene to still have the overtones of "the Emperor reaching out" while still acknowledging the distrust between the parties.

I'm bringing in thoughts I've had about the "choice" about what to do with the Netherbrain, as well, so here we go.
First, there are some changes I'd like to make to the circumstances of the finale. They don't require much screentime to change, but I think they have a big impact on the weight of your decisions:
1) The Absolute did NOT transform all of the infected. This means that similar to the consequences of blowing up the brain in Act 2, there are many "hostages" in play that can still be saved if the brain is properly disabled.
2) The Absolute CAN be killed WITHOUT a mindflayer. (Only the Netherstones are required for this)
3) The "hostages" CANNOT be saved without a mindflayer. (The brain must be controlled by a mind-flayer for this to be done)

Thus:
When you are pulled into the Astral Prism, the Emperor explains that he cannot continue both subduing Orpheus and also resisting the Absolute. He's now ready to simply kill Orpheus and hope to absorb his power (if you ask him early in Act 3, he expresses doubt about it working this way). The other obvious choice is to free Orpheus and have him fight alongside you as your protector.
Also, the player character's sacrifice of becoming a mind-flayer is NEVER strictly "necessary" -- it is a choice to become a mind-flayer to spare countless others from that fate. In the current game, it's basically "become a mind-flayer or everyone dies, including you" which isn't really much of a choice. By making it possible to achieve a lesser victory by defeating the brain but losing the infected, the choice has a little more meaning to it. The alternative to this choice was having shown compassion to a mind-flayer even without having become one, and getting the Emperor to help you.

Siding with Orpheus
If you kill the Emperor and free Orpheus, then Orpheus will gladly join the cause to defeat the elder brain -- but he will NOT, under any circumstances, turn into a mindflayer himself. He's already expressed that he sees the infected as a lost cause, though he will promise that he and his githyanki warriors will help slay those who turn and protect the uninfected of the city. Now:
A) You can kill the brain, but the infected (minus the party) will also die. The party surviving can be handwaved as some combination of Orpheus's protection and possessing the Netherstones / being right next to the brain when it dies. None of the party becomes a mind-flayer.
B) You can save the hostages IFF one of the party members turns into a mindflayer. Orpheus MUST BE PERSUADED to allow this -- otherwise, he sees teaming up with a full-blown mindflayer as both abhorrent and simply too risky. If Lae'zel is around to vouch for you, he's easier to persuade. If Orpheus refuses, you simply can't turn, and he may destroy the tadpole so you can't use it. (You also need to use this path if you're planning to take the brain yourself while siding with Orpheus)
*As alluded to in one of my above comments about the Orphic Hammer -- if the party is currently holding the hammer, they can free Orpheus immediately and gain his help in the battle. If the Emperor is holding the hammer, they must defeat him without Orpheus's help, although Orpheus will still be protecting them from the Netherbrain. To explain why Orpheus doesn't just eject the Emperor from his protection, I'd say that the Emperor still has enough psychic control over him to force him to shield the Emperor, too. (In the case where Orpheus is still imprisoned, either he has enough freedom to extend his protection, despite the Emperor trying to kill you, or the Emperor would rather fight you as you are than fight you-controlled-by-the-Asbolute).

Siding with the Emperor
If you kill Orpheus and side with the Emperor, how this option plays out is now dependent on where the Emperor stands on his Trust / Distrust meter. If he's somewhere in the middle, there will be a chance to talk to him right as he's primed to take control of the Netherbrain. If he's too far to either side, then he'll act on his own.
A) If he's on the Trust side, he will use his control over the brain to free the hostages, as promised, and then kill the elder brain. (Or, if you want the Absolute to rule the world, you can convince him to do so)
B) If he's on the Distrust side, he will seize the opportunity to try to control the brain and take over the cult of the Absolute. The party can battle him here, and although it might require some skill checks to grab the Netherstones from him.
In either case, if you're a mindflayer, you can try to seize the brain instead of him.

Siding with Both the Emperor and Orpheus
Here's where the Trust path with the Emperor will really pay off, if you pursued it. The Emperor starts out very strongly against the idea of releasing Orpheus, as he expects Orpheus to simply try to kill him (and the party) and assumes that Orpheus would not work with a mindflayer under any circumstances. If the Emperor is too far down the Distrust path, he simply cannot be persuaded otherwise. If he's on the Trust path, the player will have the opportunity to make the case to him that it would be better for all of them to attempt an alliance.
Here are some arguments the player might make:
- Orpheus hates the Netherbrain and the Grand Design far more than one lone mind-flayer who is clearly working against the brain
- The Emperor was uncertain that the power can be transferred; Orpheus willingly joining them nullifies this concern
- The alliance is so unthinkable that even the Netherbrain won't see it coming (one of the lore books mentions something like this about elder brains)
- Telling the Emperor that if Orpheus refuses the alliance, you'll side with the Emperor (you don't have to follow through)
- Asking the Emperor to trust in the player's judgment, pointing to their track record up until now
If the Emperor is successfully persuaded, he will relax his hold on Orpheus enough so that Orpheus can speak to the party, although the Emperor is still forcing him to protect everyone from the Netherbrain. Now, the party must also speak to Orpheus and argue their case to him, too. Orpheus is likely to raise the concern about the Emperor betraying you (the thing that will happen in the Distrust path) as well as his general stance against mindflayers. He'd try to convince the party to simply free him, as the Emperor clearly does not have the mental resources to subdue them all at once anymore. The party can make arguments about trying to save the people who have been infected, as well as possibly defending the Emperor if he's been helpful, even if he protested at first.
If both are convinced, then an alliance has been forged. At this point, the Emperor's Trust path will be locked in, and he won't try to take the brain. Orpheus also has no intentions of betraying this agreement (the player still can, though).
With Orpheus protecting the party and the Emperor acting as your mindflayer, the brain can be killed and the hostages saved, without any member of the party having to turn into a mindflayer (unless you just felt like it -- presumably suggesting to them that having a backup mindflayer would be safer).
After helping save the city, Orpheus and the Emperor leave peacefully, as they each do in their current respective endings.

My intention here is to make players feel as though the choices they make with the Emperor have meaningful impact, as well as to give resolutions to both those who like the Emperor an those who hate him. And my approach to this was having a universal "worst option" on the table, with the good endings being different choices of how to avoid it. In other words, the endings could be ranked something like this:
Worst Ending -- Orpheus is killed, but the Emperor betrays you. No one wants this outcome; it is a failure, but where exactly you failed is a matter of interpretation.
Good Ending (For those who hate the Emperor) -- Free Orpheus, fight the Emperor. Optionally, become a mind-flayer to save the infected.
Good Ending (For those who like the Emperor) -- Convince Orpheus and the Emperor to work together. For a lesser victory, the Emperor makes good on his word, but Orpheus was killed.
In either "good" ending, you're rewarded for putting in the effort to properly "deal with" the Emperor and avoid the worst outcome, by your preferred methods. Either you made sure to secure the hammer and then attacked him when the time was right; or you worked to reform him and convince him that an alliance was a better approach. While I do think the "work together" path has some slight overtones of being a "best ending," I still want "Free Orpheus, Kill the Emperor" to feel like a major victory, since I think a good portion of players would prefer something like that.