Impostor Captain Tennille

"Troublesome waters! Lies and betrayal! It represents the fear of the unknown: the card of the moon, Dark Blue Moon!"

- Impostor Captain Tenille

The Impostor Captain Tennille (偽キャプテン・テニール) is an unnamed tertiary antagonist featured in the third part of the JoJo's Bizarre Adventure series, Stardust Crusaders, specifically the "Dark Blue Moon" story arc.

He is an assassin sent by DIO who fights the Joestar Group in the middle of the ocean on their way to Egypt. He is a Stand User and wields Dark Blue Moon.

Appearance
Tennille appears as a tall, muscular man possibly in his late thirties. He has a fairly inconspicuous appearance as he only has a moustache and a soul patch for a facial trait and has a mere crew cut.

His attire is similarly ordinary as he wears a simple shirt and trousers, complete with gloves, a plain kerchief tied around his neck, and a captain's cap.

Though the true Captain Tennille is never shown, one can assume that he was practically identical to the impostor, since his men, who had worked for ten years on the same ship, did not even suspect the replacement.

Personality
Tennille appears to be very patient, as he originally planned to separate the protagonists and kill them one by one. Once his schemes are spoiled by Jotaro Kujo, he does not lose his calm, saying that it will be no problem for him to kill them all at once from underwater. He appears to be also quite thorough in his work as he planted bombs on his ship to prevent the Joestar Group from sailing to Egypt. He also enjoys guessing what his enemies are thinking. As with most Stand Users, he is very confident in his Stand's ability, with reason as even Star Platinum had trouble fighting Dark Blue Moon in the water.

He also seems to be fond of the ocean, as he confronts Jotaro after seeing him smoking and puts out the cigarette on Jotaro's cap, asking if Jotaro was going to throw the ashes and the cigarette in the water, which implies he dislikes seeing the waters being polluted (although this clashes with the fact that he disposed of the real Captain Tennille's body by throwing it into the ocean).

Stand
Tennille's Stand is Dark Blue Moon, a considerably independent humanoid Stand of great advantage in water due to its ability to swim, create whirlpools, throw its razor scales as projectiles, and create barnacles that drain the strength of its foes.

Lung Capacity
Tennille's lung capacity surpasses the human average by three times, and through practice, he can stay underwater for 6 minutes and 12 seconds.

Background
Tennille is one of the Tarot Card representatives sent by Enya the Hag to kill the Joestar group. Seeing that the Joestar group decided to travel by sea after the attack of Gray Fly and how the captain of the ship looks just like him, he decides to kill the captain and take his place. He throws the captain into the ocean and boards the ship with everyone else, no one noticing that he isn't the real Tennille. He plans to kill the group one by one while inside the ship.

Stardust Crusaders
Tennille appears on a boat that Jotaro Kujo and company have taken to go from Hong Kong to Singapore. After Jotaro and Anne are attacked in the water by a mysterious creature, Jotaro has become suspicious of the crew members and believes one of them may be a Stand user.

Although Joseph Joestar insists that the Speedwagon Foundation had checked his credentials, Jotaro decides to find out if he is the culprit anyway by playing a bluff on him: he says that breathing even a minimal quantity of smoke causes a big vein to appear on the nose of a Stand user. The impostor Captain Tennille immediately falls for it, and reveals his true identity and that he had killed the real Captain Tennille earlier in Hong Kong Harbour.

He tries to take Anne hostage, but before he manages to do so he is stopped by Star Platinum. Tennille, however, drags Jotaro underwater with his Stand Dark Blue Moon, where his Stand can fight at full power. He traps Jotaro into a vortex, attempting to slash him with Dark Blue Moon's razor scales. He even manages to create some sort of little Cirripede-Stands that drain energy from his opponents' Stands.

Finally, by exploiting Star Platinum's ability to stretch his index and middle fingers, Jotaro stabs the enemy Stand and rips half of his head, defeating him, but in a last ditch effort, the impostor Captain Tennille blows up the ship, leaving the protagonists to meet their next Stand encounter, Strength. Tennille, however, is left to die in the sea.

JoJo RPG (SFC)
The events from Dark Blue Moon occur on some different ways from the original story, as the impostor Captain Tennille uses his Stand to attack the party within a water trap found in a building. Also, Anne is completely removed from the game, resulting in the impostor Captain Tennille not using her as a hostage to attack the team.

Heritage for the Future (PS1/DC/Arcade)
Unlike the previous game, the events from Dark Blue Moon appear on the game with nothing removed. It appears as a "quick time event" mini-game in Super Story mode, where the player must dodge all the attacks from the impostor Captain Tennille's Stand. The mini-game can be replayed on Gallery Mode (Oingo and Boingo's book).

Trivia

 * The impostor's true name was never revealed. In supplementary merchandises, he is still only known as "the impostor Captain Tennille".
 * In the official subtitles on Crunchyroll and the English Dub the impostor Captain Tennille is renamed Captain Dragon. This name change actually still ties into the Captain & Tennille reference, as the Captain's real name is.