Her Majesty's Dog vol 01

Amane has a unique power: if she knows someone's true name, she can control his or her spirit. Because of her unusual stoic attitude and suboptimal social skills, she is seen as creepy by her peers and has a hard time making friends. The only "person" she really talks to is actually her guardian in disguise: Hyoue, a dog-demon, who feeds off of humans' life energy. Amane "feeds" him by kissing him in public, which doesn't with help her public image. Amane and Hyoue must keep their powers a secret while fighting the evil spirits they encounter.