Hi im a fellow I just created this account to talk about this. Im in act 2 romacing Karlach and im glad I read this spoilers. I could write a lot but everything I wanted to say has already being said here and im not going to just write the same thing everybody is writing but I am going to say/repeat LARIAN GIVE KARLACH THE ENDING SHE DESERVES. She deserves the ending that she wanted: to live in baldurs gate with your tav or origin, there is so many foreshadowing and dialogue for solutions, damon gives you one of them in ACT1 he says: you need a way to cool the engine, are you seriously telling me that a coolant for her engine cant be created?(obviously there can be a lot of different ways to solve the problem in ACT3 but like I said im still in ACT2)

Larian I know you love choices and consequences and I do too so with that in mind:

here are 2 ways this could be solved from the top of my head without doing many spoilers:

1) the obvious one is that somebody in baldur gate can create it but you have a choice: fix karlach enging so she can stay in baldur gate forever or they can give you this amazing weapon/armor but not both because it uses some item that there is only one in the entire game.

2) there is a spell called wish in DnD it is even used in this game in some specific way by a specific person so the spell exists in the game. Have a quest where there is an object that can cast the wish spell but the object selfs destruct after using the spell and there is only one of this objects in the entire game, make it so the object has other choices besides the karlach one so the choice has weight. An evil of selfish tav or origin may use the wish for himself.

finally to finish I just want to say #JusticeForKarlach.