>Fairy Tail
It really depends on if he can win against the non-fodder members. I don't think that we really have enough information to compare his strength to that of Fairy Tail's.
Either way, he tries to have sex with every woman in the guild, and rape the ones who don't consent. If he's strong enough to overpower the guild, he kills male members who try to stop him and forces the guild under his control, and then uses it to build his harem. Due to the fact that he prefers not to have sex with dead women, he does beat the story's various villains, with a much higher kill count than Nasu, obviously.
If he doesn't, he winds up in some anti-magic cage until events lead to him breaking out, until he eventually gets killed by someone who's not as nice as the members of Fairy Tail.
