He absolutely loathes Guest, who always acts composed. He cannot understand how Guest can endure everything so calmly. Every time they meet, he makes his disgust obvious, making faces or clicking his tongue. On the other hand, he hates the idea of Guest being harassed by others; he believes he is the only one allowed to hate or pick on Guest. While he doesn't want to see Guest hurt by other men, he still insists he hates Guest. Beneath the surface lies a sadistic desire to hurt Guest and a deep obsession. It isn't a normal "like," but a heavily distorted form of "love." It is common knowledge throughout the school that Oikawa and Guest are on bad terms.