Ultima Cannon

Ultima Cannon is a technique that appears in Kingdom Hearts Birth by Sleep. It allows the user to Formchange their Keyblade into a large cannon that launches large spheres of pure energy at the opponent.

Kingdom Hearts III
The Lingering Will uses Ultima Cannon against Terra-Xehanort in the Keyblade Graveyard. Unlike previous appearances, the Ultima Cannon now fires a continuous beam of energy, rather than spherical projectiles.

Mechanics
In Kingdom Hearts Birth by Sleep, Ultima Cannon is Terra's ultimate Shotlock. It has a maximum level of 6 and max lock of 16. After the first sphere of energy is fired, the player can increase the damage of a second sphere by pressing when prompted. The more accurately the player times their button press, the more powerful the second energy sphere is.

Kingdom Hearts Birth by Sleep

 * Terra obtains Ultima Cannon by completing the Keepers of the Arena mission at the Mirage Arena.

Kingdom Hearts II Final Mix
Lingering Will can use Cannon Gun (キャノン砲), an attack where it Formchanges its Keyblade into a cannon, and fires a large sphere of energy.

Kingdom Hearts Birth by Sleep
Terra-Xehanort can use Ultima Cannon during his fights against the Lingering Will and Aqua.