Any last words before I blast you into a million pieces?
In the game, he is found and resides in the Lilo & Stitch-based world of Deep Space. Holding a desperate struggle to retain the dangerous Experiment 626, it is both on and before his quest to recapture Experiment 626 that he crosses paths with Terra, Ventus, and Aqua.
Gantu appreciates his position of authority amongst the military forces of his world, but his great size and strength often lead him to underestimate those smaller than he is. He shows no tolerance for failure, ensuring underlings do as told. Gantu also demonstrates a great loyalty to the Grand Councilwoman, displaying equally powerful negative feelings towards Experiment 626 and his friends: Terra, Ventus, and Aqua.
Serving no one besides the Grand Councilwoman and, to an extent, himself, the Captain of the Galactic Armada defends his ranking through any means possible, even aggression. Despite Gantu's intentions, be they good or bad, personal relations between himself and others, as well as his own jealousy and greed, often lead him into trouble.
Gantu is a whale-like, steel blue-skinned alien who towers over most beings. Dressed in a sleeveless, black Captain's uniform, this uniform has red lining and includes a small, gold badge, which Gantu pins to the left side of his chest. He also wears black gauntlets over his wrists. Gantu has three fingers on each hand, hosting elephant-like feet with three very short toes and black toenails on the end. His head has some fish-like qualities, an example being a "dorsal fin" on the top of his head's center and a noseless face. Twin, fleshy, curved "tusks" also protrude from either side of Gantu's head. His teeth are quite small and come to a slight point. Gantu lastly has slanted, blue eyes that lack pupils. A teal holster, strapped to a belt around his waist, of the same color, holds his blaster when it's not in use.
Gantu first appears alongside the Grand Councilwoman after he reports capturing a strange being floating through space, showing her an unconscious Terra in one of the ship's prison cells. The two aliens are soon attacked by a group of Unversed, Gantu attempting to defend the Grand Councilwoman but eventually forced to flee while a recently awakened Terra takes on the mysterious creatures.
When Aqua arrives in Deep Space, she is captured by Gantu, who is on the search for the renegade Dr. Jumba Jookiba and Experiment 626, and branded an intruder by the massive extraterrestrial. She is then taken to the Grand Councilwoman. Gantu is criticized when he tells the Grand Councilwoman the ship's weapons are no match against the Unversed. Aqua is hired to eliminate them in his place; she is also told to search for Experiment 626 and Jumba. When the Keyblade wielder finds the fugitives on the docking bay, Gantu ultimately attacks with a desire for revenge, intent on eliminating all three of them.
Although he puts up a difficult fight, Aqua manages to defeat him with Experiment 626's help. Witnessing his attack on her security monitors, the Grand Councilwoman arrives on the docking bay after the battle between Gantu, Experiment 626, and Aqua has ended, demoting Gantu back to Patrol status despite his protests.
Having recaptured Experiment 626, who had escaped during Terra's visit and was later given a fighting chance at survival for learning about friendship during Aqua's visit, Gantu is interrupted from tormenting the small alien. Soon after, an intruder is detected. He finds Ventus, whom he accuses of being the trespasser. Ventus explains he is merely following an Unversed that had snuck aboard the ship, Gantu calling him a liar, since no other intruders had been sensed.
However, the Grand Councilwoman's announcements of a monster causing the engine to go wild and out of control make him change his mind and pursue the creature. Ventus then proceeds to disobey Gantu's orders to stay put, defeating the mysterious Unversed alongside Experiment 626. Ventus and the renegade Experiment 626 affirm their friendship, but then Gantu arrives in an attempt to destroy them. He is out-maneuvered, and Experiment 626 is able to escape the ship.
Gantu utilizes his enormous size, strength, and weapons to his advantage in battle. He is able to perform devastating charging attacks, as well as fire a blaster. He can punch and crush enemies, and only the combined ability of Aqua and Experiment 626, Astro Shot, can stun him. Despite his weapons and size, however, it is implied Gantu is not much of a threat; upon his defeat in Kingdom Hearts Birth By Sleep, he exclaims, "Oh no, not again!", implying a previous failure in combat.
Similar to his role in Kingdom Hearts Birth by Sleep, Gantu served as the main antagonist in his film debut, Lilo & Stitch, as well as in its spin-offs and sequels. He originally aided the Grand Councilwoman on Planet Turro, responsible for sentencing Dr. Jumba Jookiba to imprisonment. Gantu was later sent aboard a spaceship set for a desert asteroid and containing Experiment 626, who was sentenced to exile.
Experiment 626 escaped, much to the Captain's displeasure. After Jumba and Pleakley failed to capture 626 on their own, Gantu was then sent to Earth in an effort to recapture him. He failed, leading to the Grand Councilwoman forcing his retirement.