Kingdom Hearts Unchained χ is a free-to-play RPG and an adaptation of the browser game Kingdom Hearts χ, for mobile devices. It is a prequel to the series as a whole, set 100 years before the events of the original Kingdom Hearts. It takes place during the Keyblade War and the player's character is a Keyblade wielder who joins one of five unions who fight for the remaining light in the world after darkness has swallowed almost everything. Typical for the series, Square characters are mixed with licensed characters from many Disney franchises.
After creating a custom character and joining one of the unions, various small quests can be completed, each time in a small, separate area, to grow more powerful. Between quests and also during gameplay there are often cut-scenes where the story is furthered. Areas can be explored freely and usually have a target enemy that needs to be defeated to complete the quest, but there are also many other enemies (called Heartless) that can be engaged. The character can be moved around freely by pointing where to go using touch and tapping is used to initiate a fight. The fights are turn-based. It is possible to attack a single enemy, or all at once or only specific ones, dividing damage, using swipes.
The main Keyblade weapon can be upgraded with items and various types of blades can eventually be chosen prior to a quest based on the type of enemy. Medals are another important way to attack. These are Disney and Square characters rotated from a selection of five, also assigned before starting a quest. Each character represents a specific type of attack. These are tied to a simple colour systems (red, green, blue) with a rock-paper-scissors system for strengths and weaknesses. The special attacks with medals consume a special meter and cannot be used all the time. Additional medals are earned by completing quests and secondary objectives. Medals can be fused to create stronger ones, supporting both leveling and evolution. There is also a social aspect where medals of friends can be used. Medals have their own leveling system and statistics such as experience reward, strength, defense, damage, cost, and gauge consumption.
Next to items and medals as loot, Lux is the main currency to level up the character. There is another currency called Munny and the premium currency Jewels to get powerful medals, upgrade equipment and get more inventory space. Another currency called Avatar Coins is used to unlock nodes on boards, also earned during quests, providing perks and new customization options. This is similar to the Sphere Grid system of Final Fantasy X. Battles consume action points needed to start quests. In this energy/stamina system these are replenished over time by waiting, reach a new character level, or by spending Jewels. Next to the regular quests there are special, temporary events and raid battles against giant bosses.