Because I'm Your Buddy.

Nishio, who makes a living as an exorcist, was inspired to pursue this path by Nagumo, who saved him when he was a child. However, the once strong and cool Nagumo is a far cry from his former self—he’s constantly being possessed by spirits, forced to dress in women’s clothes, and even grows cat ears; he’s just a complete joke!! To make matters worse, physical contact is required to restore his vitality, and whilst he grudgingly goes through the motions as his partner, he’s at a loss as to how to deal with the admiration and possessiveness he can’t shake off!?