The story centered 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 were able to organize them into decks.

The story centered 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 were able to organize them into decks.