Forest Spirit, also called Shishigami (シシガミ) and Night-Walker (デイダラボッチ, Deidarabotchi), is a supporting character in Princess Mononoke. It is known as a god of life and death.
Obviously, don't nominate any human characters. Hybrids like Cheetah or The Lizard are okay, as are shapeshifters with one set animal form (eg Professor McGonagall.)
