Cards (KHχ)

Cards are the most important gameplay mechanism in Kingdom Hearts χ[chi], greatly boosting the Players stats, providing the active and passive abilities as well as making use of special skills.

Story
When the Player first arrives in Daybreak Town, Chirithy explains that cards or fragments (フラグメント) are needed to draw out the power of the Keyblade. Shortly after a Moogle bestows the Player with his or her first set or cards.

Card Types
The cards are divided into Attack cards and Assists cards and can be categorized by rarity, which spans from normal (N/N+) over rare (R/R+) to super rare (SR/SR+), by card type, or by alignment.

Attack cards (アタックカード) determine the player's attack and defense values. There are three types: Power (パワー), Speed (スピード) and Magic (マジック), each with a different set of abilities and preferred by certain Keyblades, increasing their attack values momentarily. All full attack deck consists of nine cards.

Assist cards (アシストカード) are responsible for the maximum number of health points and Lux gain rate. Usually Assist cards don't have abilities, a full assist deck contains five cards.

Additionally, cards with a rarity of R+ and better can be imbued with certain skills to expand their abilities or increase their stats, newly released cards will be boosted for a set period of time.

The alignment is mostly a cosmetic value that doesn't make much difference in the main portion of the gameplay, while it can trigger an additional damage boost called EX Card Bonus (EXカードボーナス) during raids when using the correct Keyblade with the corresponding cards. The standard cards that the game was released with are called Upright cards (アップライトカード) and only depict the heroes and supporting characters with a bright yellow and gold color scheme while the Reverse cards (リバースカード) only show the villains and enemies in a dark blue and purple color scheme.

Boosting
New Attack cards are released in a two weeks cycle, while new Assist cards are only released every four weeks. Usually these cards will be boosted until the next cycle, meaning their stats are multiplied by a factor for this time. Normally the factor is tied to the rarity of the cards, the stats of R+ cards will be multiplied by 1.5, stats of SR cards by 2 and stats of SR+ cards by 3, occasionally also by 4.

It's also possible to boost cards by yourself using special Fairy Godmother cards, this boost will last a week and is also tied to the rarity of the Fairy Godmother card. A boosted card can not be boosted again as long as it's still affected by said boost.

Level up
Depending on the card's rarity it can level up a certain number of times to improve its stats. The only way to achieve this is by fusing another card to it.

The amount of experience points gained from these material cards is again dependent on the rarity, the level of the used cards and the cards' type. For example a R+ card will provide more experience than a N card, while a card that is already on a certain level will also give more experience than a card at level 1. Using a material card of the same type as the base card to level up (e.g. using a Speed card to level up another Speed card) will result in a 1/6 experience boost. Furthermore there are special Moogle cards which will provide a huge EXP boost.

Each material card that is used for synthesis costs also a specific amount of Munny which is tied to the card's level. Occasionally the game will half the synthesis costs or double the received experience from material cards for a limited amount of time.

Limit Cuts and High Purity
When the card reaches its maximum level it can't be leveled up further without using Limit Cuts (リミットカット). To Limit Cut a card it has to be synthesized with a duplicate of this card or alternatively with a Yen Sid card of the same rarity. Each Limit Cut raises the maximum level of the base card by 5, the maximum number of Limit Cuts is once again depended on the rarity of the card.

When a card hits its maximum level after all Limit Cuts have been used up, it reaches High Purity (ハイピュリティ), its background is changed to rainbow colored one and it receives a permanent stat boost.

Ultimate cards and Rebirth
If a SR+ card has been "high purified" it can become an Ultimate card (アルティメットカード). To ultimise a card three Gems (魔石) are needed, with their nature being depended on the card's type and alignment.

An Ultimate card receives a fourth skill slot, a new border and can be synthesized with other SR+ material cards to transfer a randomly chosen fraction of their stats to the Ultimate card. This can only be done a definite amount of times and once this number is reached the Ultimate card can go through Rebirth (転生). A Rebirth of an Ultimate card once again requires Gems and lowers the stats of the card to the original High Purity stats plus a set fraction of the collective transferred stats but also allows the Player to synthesize the cards with even more SR+ material cards for an even bigger number of times and higher maximum stats.

There is also the option to reset a card to its original High Purity stats and number of Rebirths with a Remembrance Gem (おもいでの魔石). Using it also provides the player a certain number of Moogle material cards for each time stats were transferred to the Ultimate card.

To reach the maximum stats of the Ultimate Card it's essential to use highly boosted SR+ material cards instead of unboosted ones and boost the Ultimate Card before it's going through Rebirth to increase the fraction of stats that will be reduced.

Acquisition
The Player can earn new cards by defeating Heartless, open chests, trading Medals or performing card draws using Mog Points, Tickets or Charge Munny. Often timed missions or action will also reward the Player with limited cards.