Rayleigh Silvers

Silvers Rayleigh, also known as the "Dark King".

Rayleigh is a coating mechanic at the Sabaody Archipelago and he is also an expert in the coating business, as he performs such operations for various pirate ships heading down to Fish-Man Island, and he understands the workings of deep-sea currents.

Trivia

Silver is traditionally considered the next most valuable metal after gold, and as the first mate, Silvers Rayleigh was the second highest ranked man in the crew after the captain, Gold Roger.

Rayleigh appears to be left-handed. He has wielded his sword using his left hand on a few occasions.
Rayleigh is the first known character to have seen the Straw Hat worn by all 3 of its known owners.

He's the former vice captain of the Roger Pirates and is also known as "The Pirate King's Right Hand." He's a friend of both Hatchan and Shakuyaka since earlier. Like Shanks, Silvers has displayed the possesion of a monstrous "spiritual aura" or "Haki." He has also displayed an incredible fighting strength, fighting par-on-par with Kizaru using a normal sword imbued with Haki.