Thunder Boost (サンダーアップ Sandā Appu, lit. "Thunder 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 Thunder-based attacks. In Kingdom Hearts: Chain of Memories, "Thunder Boost" is activated by the Yellow Opera card, costs 20 CP to add to your deck, and lasts for 1 reload, while in Kingdom Hearts II, it requires 5 AP to equip, and in Kingdom Hearts Birth by Sleep, up to three copies of it can be equipped.
Learning Thunder Boost
Kingdom Hearts: Chain of Memories and Kingdom Hearts Re:Chain of Memories
- The Yellow Opera card has "Thunder Boost" as its ability.
Kingdom Hearts II
- Sora learns Thunder Boost at level 41 with the Dream Rod, 53 with the Dream Sword, and 99 with the Dream Shield.
- Donald learns Thunder Boost after freezing the computers at the Dataspace.
- Jack Skellington has Thunder Boost as a default ability.
- Tron learns Thunder Boost after downloading the MCP-killer program
- The Photon Debugger has Thunder Boost as its Equipment Ability.
Kingdom Hearts II Final Mix
- Sora learns Thunder Boost at level 41 with the Dream Rod, 53 with the Dream Sword, and 99 with the Dream Shield.
- Donald learns Thunder Boost after freezing the computers at the Dataspace.
- Jack Skellington has Thunder Boost as a default ability.
- Tron learns Thunder Boost after downloading the MCP-killer program
- The Photon Debugger has Thunder Boost as its Equipment Ability.
- The Meteor Staff has Thunder Boost as its Equipment Ability.
- The Shock Charm+ has Thunder Boost as its Equipment Ability.
Kingdom Hearts Birth by Sleep
- Thunder Boost can be attached to a type I or type J Command recipe through Command Melding, either randomly or by applying a Shimmering Crystal.