Marco

"Phoenix" Marco is the first division commander of the Whitebeard Pirates.

Appearance
Marco is a slim blond-haired man of average height, with dark skin and a rather sleepy look. While his chest was barren in his initial appearance, in his subsequent appearances he has the cross and crescent moon mustache symbol that resembles a silhouette of Whitebeard's Jolly Roger tattooed on his chest after Oda changed it.

Personality
Marco appears to be a patient and calm mild-mannered man. He is knowledgeable in the sense that he knew about Shanks' powerful Haki. He clearly cares for his crew because he warned them to stay back to avoid Shank's Haki.

Abilities and Powers
As commander of the first division of the Whitebeard Pirates, Marco has authority over the lower-ranking subordinates. In addition, he is also one of the top four commanders of the Whitebeard Pirates, making him one of the top four fighters on board under Whitebeard himself.

He is capable of retaining consciousness despite the powerful Haki of Shanks, a Yonkou.

He has incredible reflexes, as he is able to instantly respond to Kizaru's light-speed movement and attacks to protect Whitebeard. He was also able to touch Kizaru, who is normally intangible due to his Logia ability. This may indicate that Marco is capable of using Haki.

Marco possesses super-human strength, as shown when he kicked Kizaru down to the ground at extreme speed, however it is unclear if it's natural or comes from the fact that he is a zoan-user.

Devil Fruit
Marco ate a Devil Fruit referred to as a Mythical Zoan that turns him into a Phoenix. This first and foremost gives Marco increased speed and flight, as well as the possibility of launching aerial attacks. Along with being able to transform into a blue phoenix, the fruit allows him to regenerate any wounds with fire. It is a power that is said to be even rarer than Logia. The fruit gave him his nickname: Marco the Phoenix. Marco has more control over his devil fruit than any other zoan-user to date, it's so great that he can change just some limbs while the rest of the body remains human.

Jaya Arc
He first appeared as a background character; when Rockstar asked if anyone knew him, Marco answered "Nope, never heard of him".

Post Enies Lobby Arc
He next appeared when Shanks came to visit. He appeared to be fairly well knowledgeable and experienced with dealing with Shanks since he knew exactly what would happen to the younger crew members in his presence. He also told the members still standing afterwards not to worry about their fallen comrades as they are just unconscious. Marco was also seen in a flashback when Ace first became a member of the Whitebeard crew.

Marineford Arc
Marco has recently shown up at Marineford with the rest of the Whitebeard Pirates and their allies from the New World. Here he states that, including him, all of the commanders are ready for a battle. With his powerful abilities given by his mythical Zoan type devil fruit, he has just nullified an attack of beams by Admiral Kizaru. They seem to be on par with one another, each calling the other out on claims of being damaged. He sees Luffy and his Impel Down team and came to realization that that was Ace's brother who he had always been talking about. When he witnesses Luffy blocking Crocodile's attempted attack against Whitebeard, he concluded that "Ace's little brother is not too shabby after all." After, Marco advised Whitebeard that Ace would be executed before schedule. Whitebeard later tells Marco that he will not forgive him if he lets Luffy die, to which Marco smiles and says "Roger".

Manga and Anime Differences
In the anime when he was first shown, he was replaced with a generic crewmember with black haired man with lighter colored skin and different clothes. This is a common mistake that occurs in transferring a scene from manga to anime and has been witnessed in One Piece before, in particular when characters are first introduced without a formal introduction.

Trivia

 * Marco shares his epithet "Phoenix" with the anime only character Puzzle; but they each gained the epithet for different reasons.