Maru

A male, small-breed mixed-dog owned by Ryouji. He used to tag along with the "Trio of Troublemakers," but found himself with plenty of free time once they started frequenting Jigokudo (he would walk with them as far as the shop's entrance but never go inside). However, after eating a piece of candy given to him by the proprietor of Jigokudo, he transformed into a supernatural hound; in this form, he has saved Ryouji from danger—such as by fighting off a wild dog that attacked them, or by locating Ryouji when he had become possessed by a spirit while acting alone.When Ryouji created a guardian fairy during the battle against "Happiness," he based its design on Maru's appearance.