Dark Summoner is an Android, iPhone, iPad and iPod Touch compatible app created by Ateam, Inc. It is set in a world where Summoners have ravaged the world by "summoning" creatures from parallel dimensions to do their bidding, presumably destroying civilization and leaving only a few powerful Summoners in existence.
Is essentially an RPG in design, with strategy and collecting elements. The player can either do missions or battle with each other, both of which require spending points that are accumulated over time to a maximum that is determined both by player level and number of allies.
Play is focused on the collection and training of summoned or discovered monsters, who can be placed in a team of up to five and then used in battles against other players, mission bosses or special "raid" bosses (which can award the player with a special, powerful creature).
Also, the game has frequent special events, which usually are comprised of either daily login collection items, items found in missions or special missions not normally available in-game. In all these cases, the ultimate goal of the special events is to gain more powerful or rare monsters.
It should be noted that Dark Summoner is still under active development, and Ateam, Inc has stated plans to add additional features over time, including further monster customization and variety.