Dammon only tried with normal infernal iron. Gondians didn't even try. Combined they didn't try.
Exactly, how it is possible to have completed quest with "We did everything we could to save Karlach" note, when we didn't even try? The missing possibilities and dialogs with Dammon, Gondians, even Mizora and Raphael about engine fix are so obvious and yet some people still say, that story is great and absolutely fine.
Because it is. One more dialogue where someone says they can't fix her won't change that. We already knowDammon can't fix that, Gortash doesn't even try to save himself with a deal and Steel Watcher says that her engine is an old model that should be scrapped (and correct me if i'm wrong, scrapping the engine out of Karlach would kill her). When it comes to Mizora or Raphael, dealing with them would be like stabbing Karlach in the back considering she's close to mental breakdown when she enters House of Hope. Hell, that's why I think that dragging her back to Avernus shouldn't even be an option. It's a great tragedy current endings already dimnish it, I can't imagine taking it even further.
But it is not true. Exactly these few dialogs will close the whole issue, you will know for sure, that you can't help her. In actual state we are all looking for obvious solution which should be in game (and Im 100% sure, that the gondians were ment to be the solution), but we cannot find it, because it is not implemented. Damon should use enriched infernal ore which is in the game but doesn't have any purpose. Why? Because he can't. Gondians better not speak to you at all. Why? My romanced character stays next to me and I'm not able to say can you fix her? Why? Raphael and Mizora can help us, of course Karlach can hates us then, but is is my choise, Im Tav, not her. Can I ask them? No. Why? What steel watcher told us doesn't really matter. Yes she had old engine and should be scrapper and what? We're still looking for solution, we already know that she can die. BG3 is awesome game, I think one of the best ever, but the removed content hurts. And that Act3 is not completed is known thing, it is basically mentioned in every BG3 review.
