It looks like Larian has added some dialog of what appears to be a new epilogue involving Withers. From what I gather, it is probably several months in the future and perhaps involves some interaction with companions.
If that is the case, and we get an epilogue that allows us to interact/talk with companions, it might be a possibility that Karlchs epilogues involves returning from Avernus with Tav/Wyll.
If so, I'll take it. Granted, I would prefer to have her quest line expanded to include a fix, but that kind of closure would be good enough for now.
Again, not 100%, don't take it as gospel since the dialog looks scattered and is very hard to get a clear picutre, but interesting none-the-less.
