Dracule Mihawk

The world's greatest swordsman and (at the time) a member of the Seven Warlords. At the Baratie he easily defeats Zoro, becoming the rival he must surpass.

Dracule Mihawk 'Hawk-Eyes', the world's greatest swordsman and a former Warlord. He beat Zoro at the Baratie, becoming the goal he must surpass, and later trained him at Kuraigana.