This Can't Be Love

Synopsis

The king of the demon world comes to Earth in search of an Omega mate and sets his sights on Kwak Chang Min, a high school student who is not happy about having a strange floating pervert intrude upon his life. When his parents win the lottery and leave him behind to go on a world tour, his new stalker becomes even bolder. Before Chang Min knows what's happening, he's been blackmailed into letting the creep live with him and the demon has even managed to somehow infiltrate his school and become his new homeroom teacher! How long can he protect his chastity from the determined demon king??? (Source: AniList)