忍ペンまん丸

Manmaru goes to ninja school at Nenga, where foxes and raccoons study the art of assassination under a bear ninja master. He is soon thrown in to local rivalry between the Nenga school, the Koga (monkeys), and the Iga (dogs), as well as facing temptations from the Dobe, a group of dropouts from the Nenga.

(Source: The Anime Encyclopedia)