Akikan!

Kakeru Daichi opens a can of melon soda and is astonished when it becomes a girl, whom he names Melon. She is an Akikan, one of a group of special drink cans capable of taking human form and becoming linked to an owner.

Melon's arrival involves Kakeru in a strange competition intended to decide whether steel or aluminum cans are superior. As more Akikans appear around him and his friends, he must navigate their rivalries while resisting the idea that his unexpected companion exists merely to fight someone else's battle.