During this second play-through, I opted to return to Avernus with Karlach! My previous play-through, I let her become a Mind Flayer because I was partnered with Gale but I didn't want her to die, and I knew she didn't want to return to Avernus. More accurately, she doesn't want to go back there alone, after finally making such amazing friends and finding a group of people she truly loves. I didn't want her to die in Faerun, and I didn't want her to go back to Avernus alone. This was such a fantastic ending. I really love her.