Akuma-san to Outa

A tone-deaf boy named Shoddy has been kicked out of the Children's Choir. Yet, in a strange turn of events, he gets taken in by Mister Demon, who becomes his vocal coach. There's just one problem... Shoddy's songs are meant to kill demons! But despite this unlikely duo, their innocent laughter can still be heard every night from the ruins of an abandoned church.
(Source: MANGA UP!)
Note: Includes 4 extra chapters.