Bizarre

Bizarre is an infamous New World pirate who allied himself with Whitebeard.

Appearance
Bizarre is a massive man with a broad chest and long arms. He has long, grey hair and beard, and over his mouth he has what looks like a pair of metal jaws. On his head he wears a black tattered pirate hat with what looks like his Jolly Roger on it, over a purple bandanna. He sports a pair of large, square-shaped shoulder pads, and long, white gloves.

Personality
Despite his rather aggressive appearance, Bizarre seems to have some common sense, having warned Ace to ignore Akainu's insults in order to get to safety.

Abilities and Powers
Bizarre is a fearsome pirate who has managed to make himself an infamous reputation in the New World, and to ally himself with Whitebeard.

Weapons
Bizarre carries around a massive katana with a square-shaped handguard, and was seen charging forth wielding it with both hands. It might be assumed that he's proficient in its use.

Past
Some time prior to the current storyline, Bizarre became a known pirate in the New World, and allied himself with Whitebeard.

Marineford Arc
When Portgas D. Ace was to be executed at Marineford, Bizarre and his crew joined forces with the Whitebeard Pirates to save him. He was seen attacking the Marines out of the bay with his fellow allies, and later managed to enter it. After Squardo stabbed Whitebeard and claimed that the Yonkou sold out his allies to save Ace, Bizarre began to doubt Whitebeard. When the Yonkou gave the pirates an escape route, he happily understood that the Marine had tricked Squardo and rejoiced that all this was a lie. When Akainu started insulting Whitebeard in order to anger Ace, he warned the boy to ignore the Admiral and proceed in the escape, but was unable to stop him and prevent him from clashing with Akainu.

Trivia

 * Bizarre is the not the first character shown with metal jaws, the first being Axe-Hand Morgan.
 * Oddly enough, in the manga when he is seen charging into battle, his metal jaws are not seen.