Fire Boost

Fire Boost is an ability from Kingdom Hearts: Chain of Memories, Kingdom Hearts II, and Kingdom Hearts Birth by Sleep that increases the strength of the Fire spell and other fire-based attacks.

Kingdom Hearts: Chain of Memories
In Kingdom Hearts: Chain of Memories and its remake, the Red Nocturne Enemy Card grants this ability.

Kingdom Hearts II

 * The Bond of Flame Keyblade has Fire Boost as its passive ability.
 * Sora learns this ability from leveling up. When you learn it is based on which weapon you choose at the beginning of the game. This is when Roxas chooses from the Sword, Staff, or Shield.
 * Sword: Level 23
 * Staff: Level 33
 * Shield: Level 15
 * Donald learns after defeating Scar in the Pride Land.
 * Mulan learns it after removing her "Ping" disguise.
 * Jack Skellington already has it learned from the first time he joins your party.

Kingdom Hearts Birth by Sleep
Terra, Ventus, and Aqua can attach Fire Boost to type A and B recipes by applying a Shimmering Crystal during Command Meld.