Possessed

I've heard of reading a book or watching a film and empathising with a character - but this is something else...

"Otakukin believe that they, for one reason or another, have the souls of anime characters, or the souls of people/entities from worlds depicted in anime, or in other modern fiction".

But don't worry, there's a whole community of Otakukin out there and "Otakukin is not a delusion any more than any other belief or spirituality is": "A delusion is defined as 'an erroneous belief that is held in the face of evidence to the contrary'. There is no evidence to the contrary with Otas. You may not personally believe in worlds where anime exists, but you can’t prove beyond a reasonable doubt that they don’t. Neither can Otakukin prove that they do. All that Otas can offer is the subjective evidence of memories and feelings that leads them to their belief". Fair point, perhaps - though for someone who's an arch sceptic towards other forms of belief and spirituality, that doesn't make it any less insane...

(Thanks to Jon for the links.)