Cross Vol 3

Cross by Sumiko Amakawa. A Romance manga, published in English by Tokyopop.

Amakusa Takara is a young Catholic priest who exorcises demons, and sometimes the Devil himself, by summoning the sign of the cross on his forehead, a power that pushes him to the edge of pain and madness. When Shizuha, a girl who can write ancient Scripture on her body, is hunted by demons and by a cult that has drawn in her own parents, she turns to Takara for help. As she grows closer to him, she finds herself wanting to protect him in return.