wyll as the resist urge designated companion would:
bury alfira’s body with you. you can earn several approval points from this, enough to make up for the disapproval u earn killing her in the first place (if u learned how to play an instrument from her, or u are a bard, u can get an extra special cutscene where u play her song again over her grave. if you don’t, you can choose to sing what you remember of her song, and wyll will sing with u. if u vhoose not to sing at all, wyll will simply sing the song alone.)
check in with you! every time u resist the urge, wyll can see it. he doesn’t always tell u he’s proud of u, but he does always insist you go hunting together afterwards. u dont get a cutscene after the first time, but when u go for a long rest—u have a full twenty extra camp supplies of meat, and a few extra potion ingredients from where wyll pointed out the beauty of the sword coast to you, and the bounty of the land
after that hunting cutscene, wyll would admit to u he also has intrusive thoughts sometimes. killing is killing, blood is blood. violence doesn’t have to be evil, sometimes its even necessary. and you’re not evil for your thoughts, no more than he is for making his deal with mizora at all. it matters to him, that you mourn and respect the dead. it matters to him that you care, and you know when you want to do something wrong, and it matters even more that you don’t give into the urge anyway. it’s hard to be a good person, and it’s hard for him, too. he struggled, more than he wants to admit, choosing not to kill karlach. but he chose, and he doesn’t regret it. and he hopes you both keep choosing to do the right thing, even when it hurts.
it would be interesting also if he said that the voice that called him out to the cliffs that day to fight the cultists wasnt the first time he heard zariel’s voice. she tried dozens of times to corrupt him before, and after, and wyll fears sometimes she even suceeded. but the times she failed, and he triumphed, matter just as much.
and your reaction to your mistakes, the way you learn, the way you do better when u learn, the way you keep trying, every time u can, to do better. matters more than if u were perfect and never made mistakes at all
he would also call u out on ur shit tho. like bro. no. lmao, u really do have to resist the urge to gain approval, but u gain a LOT more resisting than anyone else