Devil Collection is a social card-battling game released through the Mobage service. Like other social games on the service, it is based on a free-to-play model. The story centers around players defending modern day Tokyo from a demonic invasion as a demon summoner with access to demon summoning and fusion through a cellphone application. By gathering demon companions and fusing them with customized skillsets, players are able to organize them into decks. Card rarity levels are denoted by the star values on the side of each card with Master, the highest ranking, being six stars.