Adding my 2 cents on the salt pile, 'cause if I had to make a headline for my BG3 playthrough it would be something along the lines of: "Gamer sets out on a 200 hours-long quest to fix a broken heart, gets heartbroken instead". I was honestly SO sure her quest could be resolved well, especially seeing all the other origin companions' stories unfolding...anyways, rant below, ye be warned
All origins follow a similar thematic pattern: they each struggle with an abusive figure/negative force that has had a significant impact in their lives (and, in a way, even made them who they are at the beginning of the game). Depending on the player's choices they can either succumb to it, walking down the path of self-destruction until their literal or metaphorical death, or choose to break free from it, at the cost of giving up a significant part of themselves (usually a power, belief or personality trait strongly influenced by the aforementioned force/figure); this compromise prevents the better endings from feeling either "tragic for the sake of tragedy" or "too perfect and "Disney-like"
I thought the formula above would apply to Karlach's story as well, and I was dead wrong.
In Act 1, her outburst post-Anders encounter is met by present companions with a shared, ominous sentiment of: "if she keeps letting it get too far, this power will be her undoing", an idea which I thought nothing of, at least until the matter of infernal coins (specifically, overusing them) and the "btw you're dying" reveal came up, because by the end of Act 2 I had already gotten plenty of chances to influence (or at least challenge) the other companions' personal choices (and thus, control their questlines) via dialogue, something the game had only let me do with Karlach when it came to her usage of her engine and the consumption of soul coins. I thought her "narrative split" was gonna revolve around those issues, but as it turns out there was never any splits or routes to begin with.
By the time in Act 3 when I was completing the first few companions' questlines, I was still convinced someone in Baldur's Gate was gonna offer her a permanent solution to the engine problem, with the drawback of rendering it powerless: you can live, just not as Zariel's supersoldier (which in hindsight I think would've been a meaningful bargain, considering how much she loves fighting and feeling powerful). I'd get to save her life and unlock a hopeful ending, just like I did for every other companion, or I'd do something wrong/evil and doom her to a bad fate, just like I could do to every other companion: with this thought in my silly silly brain I carried a shitload of infernal iron pieces all throughout the final stretch of the campaign, only in the end to get completely proven wrong. I finally finished the game this Saturday and was so upset at the endings that I bailed on that evening's plans (with an excuse, mind you: "no clubbing tonight, my virtual girlfriend died" didn't have a nice ring to it)
TLDR: making hopeful predictions about the plot backfired in my face horrendously lol. Also #JusticeForKarlach
Welcome to the club! I was nearing the end of act 3 and I was like there has to be something I'm missing. I had all this iron and enriched iron and I never used those soul coins during the whole game cause those just seemed like they'd make her condition worse. But nope none of that mattered cause in the end her story was predetermined from the moment you find her my the creek. It gutted me for weeks I had to stop playing the game it was just so pointless in how tragic it was compared to the others like you said. It's why im hoping for a happy ending to bring her into Line with the others.
