Ushio & Tora (1995)

Ushio is just an ordinary boy who found a magic spear under his temple home. More importantly, he also discovers an annoyed tiger-like demon named Taro, who has been pinned by that spear for centuries. Of course, Ushio doesn't release him, but the demon's exposed presence releases other dangerous supernatural creatures to the temple which forces Ushio to remove the spear, and to release the demon in order to confront the menace. The pair are successful, but now Taro is free and is itching to eat Ushio at his first opportunity. However, the spear is magically able to change Ushio into a powerful warrior and more importantly, those initial demons are but the first in a wave of mystic threats to the world. Against these circumstances, this fractious pair find themselves allies and defenders of the innocent as they learn to get along in their strange relationship.