Ushio and Tora

 Long ago, a ferocious monster terrorized the land, until a samurai, wielding the legendary “Beast Spear”, sealed him away. 500 years later, a middle school student named Ushio Aotsuki accidently uncovers the monster in a hidden cellar under his family’s temple. The unsealed monster and the spear attract many other supernatural creatures to the temple and Ushio is forced to release the monster in order to defeat them. Ushio names the monster “Tora” and unwillingly work together to battle other spirits and demons.

(Source: Crunchyroll)