Arthur

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

Appearance
Arthur is a man with a curly beard wearing a turban that covers his hair. In the anime, he doesn't have a beard.

Personality
Having only appeared on a small number of occasions, there is little of his personality that can be ascertained as of late.

Abilities and Powers
Arthur is a fearsome pirate who has managed to achieve an infamous reputation in the New World, and to make an alliance with Whitebeard. He's seen wielding a sword when Ace was burnt by Akainu.

History
Some time prior to the current storyline, Arthur 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, Arthur and his crew joined forces with the Whitebeard Pirates to save him.

He is only alongside Hangen and Reforte when they charging inside the way made by Little Oars Jr., few moments before Whitey Bay broke the wall. He's seen again alongside Doma when Whitebeard charging the Marines.

His last appearance is when Ace was executed by Akainu, he is briefly seen defending Luffy and his brother a few moments Ace's death.

Post War Arc
He, along with the rest of the crew attended the funeral of Whitebeard and Ace on a undisclosed location somewhere on the Grand Line.

Major Battles
Whitebeard Pirates and their allies vs. the Marines and Shichibukai

Trivia

 * The etymology of the name "Arthur" is disputed, but it is often suggested that the original Welsh meaning is "bear" or "bear-like", which somewhat fits the character's appearance.