Ultima Cannon

Ultima Cannon (アルテマキャノン) is a technique exclusive to Terra in Kingdom Hearts Birth by Sleep. As they are extensions of Terra, Terra-Xehanort and the Lingering Sentiment can use this attack as well. The attack consists of Terra transforming his Keyblade into a large cannon, which launches two large balls of energy at the opponent.

Mechanics
In Kingdom Hearts Birth by Sleep, Ultima Cannon is Terra's ultimate Shotlock. After the first ball of energy is fired, the player can increase the damage of the second ball by pressing when prompted. The better the player times their button press, the more powerful the second energy ball is.

In Kingdom Hearts II Final Mix, the Lingering Sentiment's version only fires one ball of energy.

Kingdom Hearts Birth by Sleep

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