Captain Shark is the formidable Pirate Battleship of the Legendra Braves, a robot designed as the secret ninth member and a hidden backup plan. Its Power Stone was concealed on the moon, intended for awakening only if the Earth’s Power Stones were corrupted.

Prince Walter Walzac, stranded on the moon during a battle, discovered the Power Stone. With his oxygen running out, he recited the summoning spell, becoming Captain Shark’s master. This alliance transformed Walter from an antagonist into a protagonist and ally of the main Brave masters.

The robot boasts multiple shark-inspired alternate forms, including a battleship and a battle tank. It demonstrates exceptional power and resilience, easily withstanding beam attacks and physically overpowering large foes. Its capabilities rival those of Great Goldran, the ultimate combined form of the Gold Braves.

Captain Shark’s arsenal includes double-barreled shoulder cannons, arm-mounted Shark Cannons, and the Captain Sword stored in its tail. Additional weapons are a Spiral Launcher missile Gatling on the left shoulder, a Shark Harken harpoon on the right forearm, and a Rocket Hook on the left forearm.

It combines with Advenger, which transforms into a massive beam cannon, forming the Hyper Galactica Buster Mode to unleash an overwhelmingly powerful attack. Captain Shark also executes the "Knight and Captain" combination attack with Duke Fire, alternating slashes with their swords.

In the *Brave Saga* narrative, specifically *Brave Saga 2*, Captain Shark reverts into a Power Stone. Sharanla safeguards it for Walter, but when Walter is brainwashed, his brother Serious requests the stone to rescue him. Captain Shark accepts Serious as a temporary leader, granting him the title "Deputy Captain of Warship."

Internally, the robot is remarkably spacious, featuring a dining room large enough for passengers to eat undisturbed even during external battles while in robot mode.