Tetsumi Onamota is an anthropomorphic ram and the first new character created for Teenage Mutant Ninja Turtles: Amazing Adventures. Tetsumi was once like a brother to Hamato Yoshi and Oroku Saki. As a child, he discovered a key that was tied to the Japanese Zodiac. Using this key, he harvested the life force and powers of animals who featured in the zodiac. This power began to corrupt him, and it cost the lives of half of the Hamato Clan. Yoshi and Saki fought and defeated him, thought by both boys to have been killed. However, he later appeared in the present, transformed into a ram man. He hypnotized Chris Bradford, Dr. Cluckingsworth, Tiger Claw, Anton Zeck, Hamato Miwa, Leatherhead, Dr. Tyler Rockwell, and Splinter to following him. He used the key to drain their powers and transformed