Opal

It might be partially narcissism, because one of the traits of a yandere is their obsession with their crush/love interest/etc. So if you're on the receiving end of that... XD

The other thing is maybe an interest in the exotic, in this case the unique personality the person has.

In reality though...that person needs help :P

Nice breakdown of that. I was actually thinking of having Opal have a small obsession with Heathcliff, if you ask Mari, all my characters from the past had some sort of obsession/infatuation with another person. BUT I might break the mold and not do that with Opal. 

Hehe yeah, don't give in to conformity! XD