Zero (KOF)

(You may be looking for Zero from the Mega Man X games)

During The King of Fighters '99, Zero was commanded to watch over the performance of the Kyo Kusanagi cloning process, set forth by one of their lower ranked officers, Krizalid. Acting as the project supervisor, he monitored all actions done by Krizalid and also analyzed the performance of K'. After he neutralizes the Kyo clones and terminates Krizalid, he begins to secretly build his own weapon from NESTS's technology called the "Zero Cannon", setting it to operate with the same technology found in Krizalid's battle armor.

He sets his plans into motion in The King of Fighters 2000. There, he impersonates Ling, a military commander and close friend to Heidern. Using his Ling persona as a decoy, he tricks and captures Heidern to stop the military resistance against him. He then fights the winning team of the tournament, planning to use their fighting capacities to power his Zero Cannon...

2D Fighters
Zero was defeated by Rolento in the opening round.