Moriko always felt drawn to the sea, being descended from a long line of ama divers, and living on an island that thrived on aqua-tourism. It wasn't until after she was drummed out of the JMSDF's Special Boarding Unit for assaulting a superior officer in spite of a promising career in the Japanese Navy that she realized that she realized there were reasons that went beyond her history: her birth father was a retired soldier of the underwater kingdom of Ryūgū. Attempting to visit the palace and meet with old friends of her father, she discvered that her old man had lied about the nature of his retirement: the career-ending injuries he had sustained were received as punishment for assisting in the flight of the princess O-Masa-Kōhime from the palace grounds.

Furious with her father for hiding the truth from her and for his former employer for mistreating him, as well as the Princess for not defending him, the conflicted Moriko staged a robbery of the Mikimoto Pearl Island Museum to fund a plan for revenge, purchasing surplus Black Manta resources and old Wavemen equipment to create an identity as the underwater villainess Leopard SEAL. As her plans build, she reaches out to other marine villains, including Shellestriah of the Trench....

• Equipment: a growing career of aquatic supervillainy has led to Moriko possessing a number of gadgets and tools formerly belonging to other oceanic villains and heroes.
  • Safe Harbor: a submarine headquarters made from a former vessel of Senior Waveman Otomo.
  • Leopard SEAL Armor: a combination of Black Manta, Nautical Enforcement of Macrocosmic Order, and Wavemen tech with her own modifications, Moriko's armor is specialized for fighting aquatic opponents. including gauntlet-mounted 'flashbang torpedos', strength enhancement, and
  • Flashbang Torpedos: miniature projectiles modified by Moriko from existing tech to prey upon the dark-adapted denizens of the deep.
• Ryūgūjin Hybridized Physiology:
  • Amphibious Nature: Moriko is capable of breathing water and air equally well. Due to having been born and raised on land, she is adapted to going for long periods without being submerged.
  • Enhanced Senses: Moriko hears, sees, and smells beyond human norms while underwater. She is capable of navigating in the darkness of the deep sea without assistance
  • Superhuman Bite: Moriko's natural dentition is adapted to a hypercarnivorous diet, and she is capable of exerting nearly five hundred kilograms of pressure with a bite, sufficient to tear through aluminum and crush bones.
  • Superhuman Durability: Moriko's body is adapted to the crushing pressures of the deep ocean, and resistant to decompression sickness.
  • Superhuman Strength: Moriko's muscle power is just above the limits of peak human ability.
• Linguistics: A native speaker of Japanese, Moriko speaks conversational English, French, and Trench
• Martial Arts: Moriko has a high degree of training in Self-Defense Forces Martial Arts, including Nippon Kempo-derived unarmed combat, bayonet, and knife-fighting techniques, with Moriko placing an emphasis on choke-holds.
• Seamanship: Moriko is trained to a high level in the standards of the Japanese Maritime Self-Defense Force, and is capable of piloting most marine vessels with a high degree of expertise in spite of her youth.