|This article is about the ability.|
You may be looking for the Keychain.
Ultima Weapon (アルテマウェポン Arutema Wepon) is an ability which appears in Kingdom Hearts 358/2 Days. It takes the form of a Ability Panel. It raises the Strength of the user's equipped weapon. If the weapon has a base Strength of less than or equal to +85, its bonus will raise that to +100. If its base Strength is greater than +85, the bonus will be +15. This applies both to weapons equipped through Gears and to Gear-less weapons.
 Learning Ultima Weapon
 Kingdom Hearts 358/2 Days