Abandoned by his parents when he was born with shark-like gills and teeth, Gideon Ray had a tortured childhood. As he grew, his mutation continued to alter his appearance, exacerbating his isolation. Gideon made his home beneath the docks of Independence Port, and eventually joined the crew on a modern-day pirate ship called the Black Powder. The predatory Gideon was given the nickname "Mako" for both his aquatic mutations and his vicious nature. Rising quickly through the ranks, the cold, calculating Mako eventually took over the Black Powder and made the Rogue Isles his home port.
When Arachnos took over the Isles, Mako successfully fought against them until Lord Recluse finally offered him Sharkhead as his personal domain. With his lethal bite and frenzied attacks, Mako has become one of Arachnos' top enforcers and now prowls Sharkhead Isle searching for an unknown object while "protecting" its coasts from interlopers.
As a child, Tamura Shirai was fascinated by the sleek feel of metal. Starting with a few piercings, her interest in body modification quickly spiraled out of control. Augmenting her body consumed her, and eventually she found an artist willing to fuse smooth sheets of metal onto her skin. Compulsively altering her body with the finest metals cost exorbitant amounts of money and, like any addict, Tamura turned to a life of crime to fund her obsession. Moving in criminal circles, she eventually encountered Black Scorpion. Immediately enamored with his bio-engineered armor, she joined forces with him. As Black Scorpion's assistant she quickly learned that she has a talent for murder. With the taste of blood on her lips, the woman now known as Silver Mantis commissioned a new modification: deadly metal spikes fused into her body. She is able to deal out massive melee damage to her unsuspecting enemies.