The mid and final boss of King of Fighters '99. He was created as a clone of K', but Krizalid refuses to believe this and thinks that K' is his clone.
In order to gather the battle data necessary for the activation period, he fights the winning team of the tournament. After his defeat, his superior, Zero neutralizes the Kyo clones and kills Krizalid by throwing a boulder to crush him. Heidern inquires if Krizalid remembers his real name. He simply cannot remember and dies shortly after.
He is revived later by the original Zero and fights alongside him in the 2001 tournament. What happened to him following the battle is unknown. He has yet to make another canonical appearance since then.