I was hit by the realisation that a body-hopping troll who keeps their original eyes could be identified as a lowblood because their irises "fill in with [their] 8lood pigment as [they] get older".

Shoot, you are right of course I forgot that. Maybe some troll contact lenses exist? Or if he was wearing some glasses all the time…

Or he could be actually wear some bandages around them and claim to be blind. It would work if was still able to see through any object eyes around him.