Dracule Mihawk

Dracule "Hawk-Eyes" Mihawk^[3] is a member of the Shichibukai and the current holder of the title, "Greatest Swordsman in the World". Mihawk serves as Roronoa Zoro's swordsmanship teacher during the two-year timeskip.
Mihawk is a tall and lean man with a short beard and sideburns that point upwards. His nickname comes from his strangely colored yellow eyes, which resemble a hawk's eyes.
His attire consists of a wide-brimmed black hat decorated with a large plume; an open shirt with a red-violet collar and sleeves decorated with flower patterns, leaving his neck and chest bare; a black vest and cape, colored red-violet on the inside; and white (light purple in the anime) pants held up by a decorated belt and tucked inside large boots. He wears a kogatana around his neck, appearing as a golden cross-shaped necklace, and carries Yoru on his back.
At his home in Kuraigana Island's castle, he sports different pants and an open white shirt with a ruffled neck. When he met up with Zoro outside, he had a plain dark cloak draped over his shoulders.
In Volume 63 SBS, Oda drew the Shichibukai as children. Mihawk is shown with many scratches and bruises from training. He used a bokken as his weapon. He dressed in a dark-colored open jacket, short pants, shoes and a light-colored belt.

Roronoa Zoro

Roronoa Zoro (ロロノア・ ゾロ Roronoa Zoro^?) is a pirate, former bounty hunter, and one of the main protagonists of One Piece. He is the first member to join the Straw Hat Pirates and to date is considered the largest threat and most dangerous member in the crew after Luffy. His fame as a master swordsman and his great strength, along with the actions of his captain, sometimes leads others to believe that he must be the true captain and is widely thought to be the first mate by those outside the crew. He is one of the top three fighters in the crew, and his dream is to become the greatest swordsman in the world. Zoro is labeled as one of "The Eleven Supernovas", the eleven rookie pirates with bounties over 100,000,000 to have reached the Red Line, with a current bounty of 120,000,000.