Slade Wilson

Slade Wilson, also known as Deathstroke, is a mercenary and assassin. He appears to be associated with man named Edward Fyers. When Oliver was stranded on Lian Yu, he was captured by Fyer's men who were looking for Yao Fei, for unknown reasons. When Oliver refused to give up Fei's location, he was tortured by Deathstroke. Oliver is later rescued by Yao Fei, who engages Deathstroke in battle and temporarily subdues him; escaping with Oliver.

Trivia

 * Deathstroke gave Oliver his first scar.