HemuHemu

The Headmaster's constant companion in the anime, a ninja dog skilled in ninjutsu. He walks on two feet a lot of the time, often plays shougi with the Headmaster and does odd jobs such as cleaning and bringing tea to guests. He's been trained not to bark, and his name comes from the sound he makes instead, "hemu hemu".

His main job at Ninjutsu Academy is ringing the school bell.