Caribou

"Wet-Haired" Caribou is an infamous rookie pirate who was at the Sabaody Archipelago around the time of the Straw Hat Pirates' reunion. He has a bounty of 210,000,000, making him part of the new generation of rookie pirates with bounties over 100,000,000. He is the brother of "Blood Splatterer" Coribou, another infamous rookie. Both brothers gained their reputations for killing Marines. As both of them have bounties of over 70,000,000, they both fulfill the requirement of the Impostor Straw Hat Pirates, but they eventually left upon discovering the fraudulence.

Appearance
Caribou is a tall man with dark hair reaching down to his shoulders, a distinctive wet-looking tuft giving him his epithet, and a beard in the shape of a spiral. He has psychotic-looking eyes with many circles around the pupils, pointed ears, and long limbs. He has a long tongue which is often seen sticking out. He wears a captain's coat which appears to be made of fur, dark on the outside and lighter and spotted on the inside (similar to a leopard's), dark pants and shoes, and an extremely long-sleeved shirt covered in blood with a Cross fleury that appears to be the symbol of his crew. With the way he wears his shirt, concealing his arms under his long sleeves, it resembles an unbuckled straitjacket.

Personality
Caribou is a psychotic, violent person renowned for killing Marines. He apparently believes strongly in God, begging Him to forgive the Marine that tried to shoot him, before sadistically ordering his brother to bury the man alive, as a punishment for the Marine's "sins". He later shoots the Marine when additional reinforcements arrive, as the Marine lied to him about calling for backup, without concern for the consequences of his actions. He is also very merciless, as he ignored the pleas of the fake Straw Hats.

Caribou shows a complete lack of fear of the Straw Hat Pirates (both the real and fake ones), completely disregarding the fake Luffy's orders despite knowing of his 400,000,000 bounty, and still opted to go after the real Straw Hats after escaping from Sentoumaru (though it is not known whether or not he witnessed the ease at how the Monster Trio dispatched the two Pacifista units that Sentoumaru brought with him, or even acknowledge the strenght of the real crew). Apparently, he had planned to kill the crew from within after joining, and decides to do the same to the real crew after the fakes were exposed. He also punishes the fake crew by burying them alive. All these factors strongly hints a streak of treachery and ruthlessness about him

In spite of his insanity, or perhaps because of it, he does seem to have at least some basic understanding of how corrupt the world is, as shown by his comment on how the Marines need to get rid of their "unspoken rule" about how it's okay to lie to criminals, as well as his comment on how hypocritical the Marines are. However, the former comment may be based more on his anger toward the Marine who lied to him about the reinforcements that he called than anything else.

Abilities and Powers
Caribou is a pirate captain fearsomely reputed as a killer of Marines, who has managed to reach Sabaody Archipelago, sailing through the first half of the Grand Line. In his first appearance, he was seen being able to detect the presence of a Marine hiding nearby who was spying on the recruits and reporting their presence to his superiors.

Weapons
He apparently uses some sort of spear or polearm as his weapon of choice. He was also seen using a flintlock pistol.

Devil Fruit
Caribou ate an unnamed Logia-class Devil Fruit which allows him to become and control a thick, light-colored substance similar in appearance to the wax generated by Mr. 3's Doru Doru no Mi. He was shown using it to suffocate fake Sanji by encasing his head in a ball, then allowed a cannonball fired by fake Sogeking to be absorbed harmlessly inside his body. This fruit has no apparent weaknesses, aside from the standard Devil Fruit weaknesses.

Past
Some time in the past, Caribou and Coribou became pirates and gained a fearsome reputation for killing Marines.

The Straw Hat Reunion
Eventually, the two brother managed to reach Sabaody Archipelago, where they allied themselves with the Impostor Straw Hat Pirates. They were first seen in Grove 46, their allies' meeting point, together with some fellow pirate captains. Caribou spotted a Marine spying them, injured him with his weapon, then, after begging God to forgive the man for trying to kill him, ordered Coribou to bury the Marine alive as punishment.

They were interrupted by Fake Luffy, who ordered them to stop. After the Marines surrounded the pirates at the meeting place, Fake Luffy orders Caribou and Coribou to use the Marine that they injured as a shield. Caribou refused to obey, instead shooting the Marine for lying to him. He then says that the Marines should do away with the unwritten rule that says that they can lie to criminals. He and his old crew then launch an attack. In the ensuing melee, Fake Luffy is exposed as a fraud and captured, while the real Luffy is revealed to the world.

Despite all the other recruits being captured, Caribou, Coribou, and his crew managed to escape, even capturing Fake Luffy's crew along the way. He has his crew dig graves for the fakes to be buried alive in. Caribou reveals that he never intended to follow the Straw Hats, having planned to first gain their trust and then kill them from the inside. Caribou picks up Fake Sanji and starts to suffocate him with his Devil Fruit power. Fake Sogeking then tries to shoot him, but his body absorbs the shot. He is next seen in the ocean on his coated ship, following the real Straw Hats, commenting that they better let him join this time.

Trivia

 * He has distinct Laughter Style: "keheehee".