Quil can only be encountered if the The Dark Urge is selected as an origin character. During Act 1, after meeting Alfira the Tiefling the Bard or resolving the Emerald Grove Questiline, Alfira will ask to join your camp regardless of your previous interactions with her. Moreover, regardless of your interactions with Alfira in your camp, you will be compelled to violently kill Alfira in your sleep and leave her body in the center of your current campsite in a depraved effigy. The only way to prevent Alfira from dying in this fashion is for Alfira to either be dead or knocked out before the cutscene where she is scheduled to come to your camp. If this happens, Quil will appears as Alfira's substitute and will die in her place.