Nothing game breaking or anything here, I’m not even 100% positive it’s an actual bug and not Zinnervale being an illusionist weirdo. This all takes place during the Nineveh rapport quest where Azena summons everyone to Rohendel to meet about the demon problems. Apologies, I forget to write down the name of the quest.
But, as shown in the image, “Zinnervale” is actual in the model of Thirain. Thirain is on the left there, and Zinnervale is on the right; looking like Thirain. Though he looks like himself (Zinnervale) during the cinvematic cut scene like portions of the quest; he goes back to looking like Thirain during the “walk around” portions. Talks with his voice and everything, has his name tag, but looks like Thirain.
