Thunder Boost

Fire Boost (ファイアアップ, Faia Appu, lit. "Fire Up") is an ability that appears in Kingdom Hearts: Chain of Memories, Kingdom Hearts II, and Kingdom Hearts Birth by Sleep. It increases the damage done by fire-based attacks. In Kingdom Hearts: Chain of Memories, "Fire Boost" is activated by the Red Nocturne card, costs 20 CP to add to your deck, and lasts for 1 reload, while in Kingdom Hearts II, it requires 3 AP to equip, and in Kingdom Hearts Birth by Sleep, up to three copies of it can be equipped.

Learning Fire Boost

Kingdom Hearts: Chain of Memories and Kingdom Hearts Re:Chain of Memories

• The Red Nocturne card has "Fire Boost" as its ability.

Kingdom Hearts II

• Sora learns Fire Boost at level 15 with the Dream Rod, 23 with the Dream Sword, and 33 with the Dream Shield.
• Donald learns Fire Boost after defeating Scar.
• Mulan learns Fire Boost after losing her disguise.
• Jack Skellington has Fire Boost as a default ability.
• The Bond of Flame has Fire Boost as its Equipment Ability.

Kingdom Hearts II Final Mix

• Sora learns Fire Boost at level 15 with the Dream Rod, 23 with the Dream Sword, and 33 with the Dream Shield.
• Donald learns Fire Boost after defeating Scar.
• Mulan learns Fire Boost after losing her disguise.
• Jack Skellington has Fire Boost as a default ability.
• The Bond of Flame has Fire Boost as its Equipment Ability.
• The Rising Dragon has Fire Boost as its Equipment Ability.

Kingdom Hearts Birth by Sleep

Fire Boost can be attached to a type A or type B Command recipe through Command Melding, either randomly or by applying a Shimmering Crystal.