Koko wa Ore ni Makasete Saki ni Ike to Itte kara 10-nen ga Tattara Densetsu ni Natteita.

Synopsis

The Hero's party was attacked by a large group of powerful devils. The party will no doubt be annihilated if this were to go on. One member of the party, the strongest mage, Rakku, decided to stop the enemies in their tracks. (Source: Shousetsuka ni Narou, translated)