MetalSeadramon is one of the four Dark Masters, a group of Mega-level Digimon created by Apocalymon who conquered the Digital World. He serves as the ruler of the Net Ocean and commands an aquatic army known as the Deep Savers, which includes Scorpiomon and several Divermon. Physically, MetalSeadramon is a colossal serpentine cyborg covered in Chrome Digizoid armor, with fins, two horns on its head, and a cannon barrel at the end of its snout. This form represents the ultimate evolution of the Seadramon line and was designed as an interceptor Digimon for underwater defense, completing a set that also covers land and air.

In terms of personality, MetalSeadramon is notably arrogant and short-tempered, easily losing his temper when his enemies gain the upper hand. Unlike the other Dark Masters, who may kill their minions for amusement, MetalSeadramon only executes his subordinates when they fail him. He prefers to destroy his opponents decisively rather than toy with them. His primary motivation is to maintain his dominion over the ocean and to carry out the Dark Masters’ goal of ruling the Digital World, which includes eliminating the DigiDestined.

Within the story of Digimon Adventure, MetalSeadramon is the first Dark Master to directly confront the DigiDestined after they return to the Digital World. He presides over the ocean region of Spiral Mountain, where he attempts to drown and destroy the children and their Digimon partners. His role as a major antagonist forces the DigiDestined to battle in an unfamiliar aquatic environment. Key relationships include his alliance with the other Dark Masters—Machinedramon, Puppetmon, and Piedmon—as well as his command over his aquatic minions. He shows little personal loyalty to his allies, acting primarily out of shared ambition.

MetalSeadramon's development in the series is limited to his defeat: after a fierce underwater battle, the DigiDestined manage to overcome him, and he is destroyed along with the other Dark Masters when the DigiDestined finally confront Apocalymon. In Digimon Adventure Tri, he later reappears as a resurrected Digimon, briefly attacking the DigiDestined once more but again being defeated.

Notable abilities include his signature move River of Power, also known as Ultimate Stream, which fires a powerful energy blast from the cannon on his snout. He is clad in armor that reflects or repels most attacks, and he possesses the fastest swimming speed among aquatic Digimon, capable of moving at incredible speeds underwater. In addition, he can fly despite being an aquatic Digimon, giving him strategic mobility across multiple environments. His physical strength and durability, combined with his offensive arsenal, make him one of the most formidable opponents the DigiDestined face.