However not every story needs, or should have the wines and roses happy endings.
Karlach going back to Avernus with Wyll and Tav seems actually happy to be there. The cigar scene to me is awesome. She can stay in the Realms but would have to accept being a Mind Flayer. While this might not be the life she desires it is a choice to live and then of course she can choose death.
I get that everyone wants every ending to be all smiles and giggles but the ending for Karlach, to me is not nearly as bad as people are making it. She has the chance to have two dear companions adventure with her and help her enjoy sweet revenge on those that hurt her. That seems a pretty good way to go forward in life to me.
Wanting her to live outside of hell is not the same as wanting smiles and giggles.
Also, Mindflayer Karlach is not our Karlach, it's a completely different being that simply copied her memories. We want to save the real Karlach, we don't want an eldritch cheap copy.
As for Avernus, she never wanted to revenge. That was never a plot point. It was thrust upon her at the last minute.
The things that suck the most are that 1) for an origin character, her quest is insultingly short 2) almost nothing we do actually matters for how she ends up 3) there's no sound and reasonable conclusion to her character arc.
A lot of us have said that if this was to be a tragic story or whatever, then the entire plotline should've been altered to reflect that. If she wanted revenge, that should've been alluded to multiple times throughout the story and her reluctance to go back should've never been there.
If she simply wanted to enjoy her last moments, then there should've been less hope-mongering and more Fault-in-Our-Stars'ing by spending more quality time together and tying up loose ends. For example, we could've gone out on that dinner with her friend that she promised, rather than leave it hanging.
As it stands, it's a confused storyline that needs to clarify what it wants to be. We'd prefer to save her, but at the very least make it clear that we shouldn't have these expectations.
When I played Cyberpunk, that was made abundantly clear to me. Even the open-ended hopeful ending a la Avernus was more than I thought I could bargain for since both the setting and the story were clear from the start that we were dead wo/men walking. Yet that game allowed us to try to save ourselves.
What I got from Baldur's Gate was that there are multiple pathways for Karlach to be saved, yet all of them are arbitrarily closed to us -- the Gondians, the rich infernal iron, all the spells we can cast, the pacts we can make, the gods we can plea to -- you can't look at all of that and think it's acceptible.
