Captain William Julius Jeremiah Jankin was the archnemesis of Captain Leo.
Wil has a bad leg, which he injured in WWII. Taking vengeance on Captain Leo, once his friend, (who injured Jankin inadvertantly) Jankin takes henchmen Joshua Wisteria and Damian Smith to join his team.
Leo sought the chance for a naval race on June 29, 1945. He apparently lost to Wil. Disgraced, he teleported back to the present.
Wil then took a vendetta, threatening to bludgeon him to death with toxic weapons, but had to deal with a shark Leo was going after.
Damian and Wisteria both died when their boat, the Green Lillian Namigare, sank, due to a thunderbolt catching it on fire, and the shark crushing the hull. Damian burned to death, while Wisteria got devoured by the shark. Wil escaped the burning boat.
He later tries to kill the good team, having escaped with a big chunk taken out of the boat, but the shark knocks Wil off of the boat, rips off his bad leg, and drags him underwater, devouring him offscreen.
We never see him inside the shark's mouth, but in a deleted scene of the movie, we see that his bottom half falls out, and his skin peels away, leaving his fat to fall down the throat. They deleted the scene for a good reason.
James gets eaten as well, but is vomited out as a result. He then realizes that the boat is an explosive, and lures the shark by using Kristen as bait, dipping her into the water, attaching a line to her legs, stowing it into the ground. The shark swims up to the surface with its mouth open. The team moves out of the way. A piece of Wil's skeleton (not visible) is lodged inside, and the shark bites into the boat, and explodes, vomiting out Jankin's corpse and tearing it apart in the air as it hits the water after falling 50 yards.
Morris portrayed Wil Jankin and they were both voiced by Matthew Bernstein.