Gravity

Gravity (グラビデ), Gravira (グラビラ), and Graviga (グラビガ) are spells which appear in Kingdom Hearts and Kingdom Hearts: Chain of Memories. They utilize the "power of the stars", and are associated with the Lucid material. Gravity spells form a miniature event-horizon that crushes their target, reducing their HP by a set fraction and rendering them temporarily defenseless to further attacks.

Zero Gravity (ゼログラビデ), Zero Gravira (ゼログラビラ), and Zero Graviga (ゼログラビガ) are spells which appear in Kingdom Hearts Birth by Sleep. They function much like the Gravity spells, but instead of crushing the opponent, they fling them into the air, where they slowly lose HP and may become Confused.

Kingdom Hearts
Sora and Donald Duck can obtain each type of Gravity spell, but can only cast the most powerful version they possess. Genie can use Gravira by default, however, and Jack Skellington's "Ghostly Scream" is his personal version of Gravity. Wizard Heartless also use the Gravity spell.

The fraction of HP depleted by Gravity is based on Sora's magic strength, and it is possible to deal 100% damage if the spell isn't resisted by its target. However, after Kairi's rescue, all enemies resist the spell enough so that instant defeats are not possible. The Gravity spell is also used to lower certain treasure chests at Hollow Bastion.

Kingdom Hearts: Chain of Memories
As in Kingdom Hearts, Sora can cast the Gravity spells. Genie can still cast Gravira, while Jack can cast Gravity, Gravira, or Graviga, depending on which Sleight he is summoned with. Wizard Heartless can still cast Gravity, as well.

The Gravity card can be used for many Sleights in Kingdom Hearts: Chain of Memories, all of which involve spatial manipulation or suction.

As a magic card, Gravity can also be used within the following sleights.

Kingdom Hearts Birth by Sleep
Terra, Ventus, and Aqua can obtain each type of Zero Gravity spell.

Kingdom Hearts

 * Sora and Donald obtain a Gravity element after locking the Keyhole at Halloween Town.
 * Sora and Donald obtain a Gravity element after completing the Phil Cup.
 * Sora and Donald obtain a Gravity element after defeating Hades in the Hades Cup.

Kingdom Hearts: Chain of Memories

 * The Gravity card is the Agrabah Bounty.
 * Sora learns "Gravira" and "Graviga" after obtaining a Gravity card.

Kingdom Hearts Birth by Sleep

 * Zero Gravity: Tank Toppler (25%)
 * Zero Gravira: Tank Toppler (25%)
 * Zero Graviga: Tank Toppler (5%)

Zero Gravira
Zero Gravira is an Basic-class Magic Command that can be melded through three different recipes, listed in the Magic Recipe.
 * The first recipe can be melded by Terra, Ventus, Aqua, and is a recipe that has a 10% chance of transforming into Warp when Terra melds it.
 * Thunder (LV2) + Zero Gravity (LV2)-90%
 * The second recipe can be melded by Terra, Ventus, Aqua, and is a recipe that has a 10% chance of transforming into Warp when Terra melds it.
 * Zero Gravity (LV2) + Zero Gravity (LV3)-90%
 * The third recipe can be melded by Terra, Ventus, Aqua, and is a recipe that has a 10% chance of transforming into Warp when Terra melds it.
 * Aero (LV2) + Magnet (LV2)-90%

Zero Graviga
Zero Graviga is an Advanced-class Magic Command that can be melded through three different recipes, listed in the Mega Magic Recipe.
 * The first recipe can be melded by Terra, Ventus, Aqua, and is a recipe that has a 20% chance of transforming into Warp when Terra melds it.
 * Zero Gravity (LV3) + Zero Gravira (LV3)
 * The second recipe can be melded by Terra, Ventus, Aqua, and is a recipe that has a 20% chance of transforming into Warp when Terra melds it.
 * Thundara (LV3) + Zero Gravira (LV3)
 * The third recipe can be melded by Terra, Ventus, Aqua, and is a recipe that has a 20% chance of transforming into Warp when Terra melds it.
 * Zero Gravira (LV3) + Zero Gravira (LV3)

Kingdom Hearts Birth by Sleep
Zero Gravity is used to meld the following commands: Zero Gravira is used to meld the following commands: Zero Graviga is used to meld the following commands:
 * Blackout
 * Mine Shield
 * Dark Haze
 * Thundara
 * Confusion Strike
 * Binding Strike
 * Zero Gravira
 * Warp
 * Blackout
 * Dark Haze
 * D-Link Magnet
 * Collision Magnet
 * Magnet Spiral
 * Zero Graviga
 * Warp
 * Magic Hour
 * Meteor Shower
 * Meteor
 * Quake
 * Transcendence

Notes and References
Gravité