Exorcist no Kiyoshi-kun

The most powerful exorcist in history--Kiyoshi! In order to protect that which is precious to him, Kiyoshi has attained ultimate strength. But he has a secret he can't tell anyone... Become a sword that slays evil! Become a shield that protects the weak! It all comes together in this new dramatic exorcist battle comedy series!

(Source: MANGA Plus)