Therin Gayle

A Xena type butcher turned good - http://en.wikipedia.org/wiki/Xena
Have Therin dressed exactly like the Immortals from 300... the same angled shoulder pads, two swords, etc...
Make him from Velencia - but rather than the traditional "Spartan" segment of the army, make him perhaps one of the Kings "elite guard" or something to that effect - more or less a person trained to not only be a warrior, but to excel in many disciplines - such as the use of two swords, a quasi ninja ability in stealth and assasination. Make this segment more than just a guard, also responsible for carrying out the Kings wishes when he wants things done but doesn't want things official. Also, perhaps rather than being from Velencia, he is from Velencia's main rival - perhaps a massive empire that attempted (and failed) to invade and conquor Velencia... thus he hates Velencians. Either way, don't make him a ninja - we can give that to somebody else - he should simply be a highly trained elite forces kind of soldier.