DanMachi: Is It Wrong to Try to Pick Up Girls in a Dungeon?: (Monsterphilia) Monster Festival

SINOPSIS

Bell Crannel's power grows rapidly thanks to his ability, Realis Phrase. As long as he's in love with a girl, it will continue to make him stronger. His goddess, Hestia, is jealous that the girl he's in love with isn't her, but still wants to support him. She goes to another goddess and asks her to make him a powerful sword.