@Xoldin dude was probably a loner and this event was like a trigger for his obcession for her to go to nuts level.
@Morose that's actually a really fucked up thing that botters me in most mangas, being myself kind of ugly and fat is really annoying that most fat people are or the rich dumb and bad people or the nice and funny friend of the mc and ugly people are the bad, it's like it says that ugly people are also bad and that is a hell of a shit thing to make people think.(Sorry, I get kind of fire up talking about these kinds of things lol)
So, I'm guessing that the fallen god is going to use the stalker guy as some kind of battery for him to fight the angel girl or possess him and fight the mc.