Impostor Captain Tennille

The assassin is a towering, heavily muscled man who looks to be in his late thirties. Little about him stands out beyond a blonde crew cut, a moustache, and a soul patch. The genuine Captain Tennille never appears on the page, but he was presumably a near-perfect match for the impostor, given that sailors who had served under him for a decade noticed nothing amiss.

Patience defines the impostor, who at first meant to isolate the travelers and dispatch them one at a time. When Jotaro exposes the plan, he stays unruffled, content to drown them all together from below the surface, and he takes some pleasure in reading his opponents' thoughts. He also clearly loves the ocean, snapping at Jotaro over his cigarette and demanding to know whether he means to flick the ash and butt into the water.

The impostor is one of the Tarot-themed killers dispatched by Enya the Hag against the Joestar Group. When the heroes take to the water following Gray Fly's attack, he seizes on his uncanny resemblance to the ship's captain, drowns the real man in Hong Kong harbor, and slips aboard in his place, aiming to eliminate the group one by one. His Stand, Dark Blue Moon, is a self-directed humanoid built for underwater combat, and his own lungs hold roughly three times a normal person's air, letting him stay submerged past six minutes.

On the voyage from Hong Kong to Singapore, a creature attacks Jotaro and Anne in the sea, leaving Jotaro convinced a Stand user is among the crew. Though Joseph trusts the Speedwagon Foundation's background check, Jotaro flushes the culprit out with a lie, claiming that even a whiff of smoke makes a vein swell on a Stand user's nose. The impostor bites, confessing everything, then tries to seize Anne as a hostage before Star Platinum intervenes. He drags Jotaro beneath the waves where Dark Blue Moon fights at full strength, snaring him in a whirlpool of razor scales and spawning tiny barnacle-like Stands that siphon energy. Jotaro turns the tide by stretching Star Platinum's fingers to stab and rip away half the enemy Stand's head. Beaten, the impostor detonates the ship as a parting shot and is left to perish in the ocean.