Shun Kurosaki

Shun is an Xyz user who is a comrade of Yuto's, and was also after Leo Duel School. He demonstrates a powerful hatred of Fusion Summoning. Upon having similar goals to Reiji and learning of his true target, the two agreed to cooperate. Though he implies that he may have dueled for fun before, in the present, Shun is a battle-hardened duelist who shows nothing but fierce determination and serious perseverance in his duels. Shun also carries an affection for his younger sister Ruri whom he vows to rescue. He is shown to be arrogant and is shown to have great pride in his skills. Unlike Yuto, Shun acts out more recklessly and impatient and is willing to crush anyone who he deems as his enemies, even warning Yuto not to stand in his way when focused on his goal.

[Spoiler] He later becomes one of the Lancers. [/Spoiler]

(Source: Yu-Gi-Oh! Wikia)