The King of Fighters 03: Xenon Zero (拳皇 XENON ZERO) is a eight-volume manhua series illustrated and conceived by Wing Yan and King Tung. With SNK-Playmore's permission, this manhua is the re-titled conclusion of their shorter 2003 adaption. It transitions with gameplay and story elements found in The King of Fighters XI and adds original ideas to solidify the tournament's ending.
The story takes place in the tournament's semi-finals with four teams left: the Fatal Fury team, Hero team, K' team, and the High School Girl team. The Hero Team faces the Fatal Fury in a field, with Ash winning over Terry. The High School Girl team battles K' and his team in a train. K' battles Malin who uses the limited spacing of the field to her advantage. When K' rips a hole in the cab, he eventually traps her and wins.
After his fight, K' is kidnapped by one of Dr. Makishima's agents, Kirameki Kannatsuki. During his captivity, she drills him on the "K Project" and "Krizalid Project", which were experiments conducted by NESTS to theoretically harness Orochi's power. She tells him that K' has the potential but he lacks the traits to connect with the demon. Kannatsuki tortures him to somehow invoke the link but K' is eventually saved by Seth and his agents (apparently thanks to Ron). He skydives to the tournament and makes it in time for the final match against the Hero Team. Although the battle is close, K' wins over Ash by a Time Out. While Shen Woo yells out his frustration, Duo Lon spots Ron and gives chase. Ash concedes defeat and disappears.
K' and his team are lifted to Sky Noah and are greeted by Rose. In honor of their father, she pits them against her brother, Adelheid. During the fight, Maxima is assaulted by Kannatsuki who hits Maxima's core and triggers a new mode for the cyborg: Hyper Maxima. While the two cyborgs beat one another, Whip and K' team up against Adelheid. Their teamwork fails when Adelheid drop kicks K's forehead, temporarily blinding the youth with his own blood. At this time, Rose also plays a frantic tune on the piano which drives Adelheid into a berserk rage. However, once he remembers the training session he had with Chin, K' overcomes his blindness and defeats Adelheid. Maxima also triumphs over Kannatsuki by blasting him with his Final Cannon.
Meanwhile, Ash observes the fight amongst the Three Sacred Treasure members. Kyo and Iori duel the Kagura twins, Chizuru and Maki. At first, the men lack an advantage over the sisters' impeccable teamwork. Eventually, they realize that Maki was the stronger of the two and team up to defeat her. Maki falls once she hears that she is supposedly dead. Before they can recover and discuss what had transpired, Mukai ambushes them. Ash assists the boss from the sidelines and gives Kyo and Iori even more problems to deal with. They are unexpectedly saved by Kusanagi who continued to exist even when Chizuru was passed out. He lures Mukai away from the trio, giving them to time to rest.
The scene shifts back to Rose and Adelheid. They discuss what to do with K' and his team when one of their followers appears before them. Hooked with explosives, he threatens to blow up the ship if the siblings don't cooperate. He blames them for ruining Rugal's "peerless" reputation and especially finds fault with Rose, who he says is worthless. As he tries to blow her up, Adelheid protects her but couldn't stop the explosion from blowing a hole in the ship. K', too stunned from his fight to respond, falls into the gap.
He lands on one of the lower floors of Sky Noah. When he regains conscious, he sees Kusanagi thrown onto the same floor by Mukai. He lands near K' and explains that this place has the essence of the Orochi seal. Kusanagi goes onto explain the Kusanagi clan's fate to him, knowing that he carries some of its burden within him and will someday have to face it. Before he can elaborate further, he is crushed and killed by Mukai. Enraged, K' is invigorated and fights the villain. Their battle is vicious as both sides deal heavy damage to the other. Kyo and Iori also arrive at the scene and give assistance once K's glove is smashed. Ash once again watches from afar.
As was predicted by Kusanagi, the Orochi power begins to creep its way into K's weaken body. In his mind, he sees Krizalid's spirit telling him that this was his destiny. While Orochi's emblem starts to form on his chest, the spirit of Seirah -his real sister- appears to save him. Convinced that he can form his own fate, K' rips free of Orochi's control and forms himself a new temporary glove. Revived, he confronts Mukai again and fights with him on equal ground. K' overpowers Mukai but falters for a moment due to his body's wrecked state; before Mukai can take advantage of this weakness, Ash wounds him. K' finishes Mukai off with his Crimson Star Road.
Mukai, defeated but still moving, escapes on a giant hand. On the same hand are members from Those From the Past, including Shion and Magaki. Whilst they watch them leave, Ash steals Chizuru's powers and reenacts the events in the Three Sacred Treasure's ending. Hours later, Sky Noah touches ground, and Seth, who had been observing these events, gives a report to his supervisors and hints that he also wants Vanessa and Ramon to investigate future endeavors. The manhua ends with the K' team's ending and K' walking off into the sunset.