X-Struggle/Grey's Wrath

A mysterious man creates a tournament in the center of the universe. He says that the winner of the tournament will be considered "the strongest fighter in the universe". Four heroes- Kaichu, Light Mason, Josaku, and Mizu arrive at the arena, and find that there is no audience nor any other fighters. The mysterious man reveals himself as "Grey", and asks the four competitors to step on a corner of the arena. The four heroes fight, and one (whoever the Player chose to be) is still standing in the end.

Grey congratulates the winner, and restores the four heroes to health. Grey steps out of the arena, and pounds both hands on the ground. The whole arena begins to shake, and Grey suddenly transforms into a Wingull and flies away. The four entrances to the arena are suddenly blocked off by bars, and a swirling, black vortex forms behind the four heroes. They turn around, shocked, and the votex slowly transforms into DARRXU. DARRXU sends off a large gust of wind, making the arena begin to fall apart. The four heroes fight DARRXU, and get close to defeating it.

DARRXU begins getting angry at his near-loss, and absorbs Kaichu and Josaku, making them disappear into the darkness. It gets ready to attack Mason and Mizu, the remaining heroes, when, suddenly, laser-blasts begin shooting at DARRXU. Mason and Mizu look up to see Keroro flying in on his Hover Platform, shooting at DARRXU with the Kero Ball. DARRXU begins to fall apart, but it quickly reverses itself into its void-like state and disappears. Kaichu and Josaku are still nowhere to be seen.

Keroro presses a button on the Kero Ball, making two more Hover Platforms for Mason and Mizu, and the three fly away. Mizu suddenly loses control of his Hover Platform, and crashes into both Mason and Keroro, making all three of them plummet to the ground. The three Hover Platforms land in a nearby river, making them short circuit and become unusable. The three walk on through this mysterious forest and find strange enemies that they have seen in their past. After the trek through the forest, the group find themselves at the Paucha Residence. Paucha, guarding the home, comes out and attacks the three. Mason, Keroro, and Mizu defeat Paucha in a battle.

Paucha, disappointed and embarrassed of losing, runs away into a dark jungle. He defeats several different enemies found in the jungle, and runs into a mysterious, pink-haired girl at the center of the jungle, who looks down on him, in a disappointed way. Black wings similar to those of a bat suddenly stretch from her back, and she flies away from the jungle. Paucha continues running through the jungle and battling enemies, when he runs into a Wingull at the very end. It transforms, suddenly, into Grey. He walks over to Paucha, and puts his hand on his head. Grey tells Paucha that, if he joins his side, he will never lose a battle again. Paucha accepts his request, and they walk out of the jungle.

Kaichu and Josaku lay on the ground, unable to see anything, after being absorbed by DARRXU. Josaku stands up, in hope of finding some way to get out. All he can hear is explosions in the distance, and all he can see is a bunch of white dots above him, which he assumes are stars. Josaku picks up Kaichu, and they decide to start searching for an exit. As they walk, the white dots above them begin flying down and hitting them. Some of them transform into small enemies. After a long time of walking, the two find nothing. They both lay back down on the ground.

Suddenly, they see a strange person walk ahead of them, and their body is emitting some kind of strange light. Josaku and Kaichu run over to him, and see that it is the Demon Lord, Valdrik. Valdrik tells of memories of him and Grey creating evil plans side by side, when Grey suddenly betrayed Valdrik and attacked him with DARRXU. DARRXU and Valdrik fought, but, in the end, DARRXU absorbed Valdrik, leaving him in this darkness. Kaichu, Josaku, and Valdrik decide to team up, for now. The three continue walking through the darkness, when they come across a flying, blue orb.

Kaichu walks up to the orb and puts his hand right in front of it, when he is suddenly attacked by some electric bolts. Darkrai, who was the attacker, flies in. He tells that he is the guardian of the darkness world, and that he is not allowed to let anyone leave. Darkrai continues attacking Kaichu, with different elemental attacks. Josaku and Valdrik fight Darkrai, and defeat him. Darkrai steps back away from the two, and touches the blue orb and is suddenly teleported away. Josaku and Valdrik pick up Kaichu, and touch the orb. They appear in Float City.

Paucha and Grey walk through a desert. To test Paucha's skills, Grey makes Paucha walk ahead and fight all of the enemies. After a long while of walking, the desert ends, and the two find themselves on grass. Suddenly, a missile of water comes out of nowhere and hits Paucha right on the back. The attacker was King Floatzel of the Zel Army. Paucha stands back up from the attack, and fights King Floatzel. Paucha defeats him. Grey congratulates Paucha, and tells him that they need more people like him in their team. Paucha, proud of himself, agrees. The two continue to walk on the grass.

Sispirit watches over the Center of the Universe from The Palace of the Spirits with her brother, Brispirit. She watched as everything that has happened in the Center of the Universe took place. She watched Paucha join Grey, which she couldn't allow to happen. Sispirit and Brispirit leave the castle, and go across a trail of clouds to get to Paucha and to save him. Once they arrive, Paucha and Grey are walking across a field, and the spirits attack Grey. They defeat him, but he quickly restores himself to health.

After that, Paucha attacks Brispirit and Sispirit, and Grey helps out in the battle. One side (whichever team the player decided to play as) wins, and Grey restores all of the group to full health. Grey tells the spirits that he appreciates their strength, and that he would love for them to join his team. The spirits deny and attempt to get Paucha back, but Paucha refuses for them to get him. Grey requests for them to join again, but this time, holds out a mysterious stone. Brispirit suddenly changes his mind and joins Grey's team. Sispirit, shocked, attempts to get Brispirit back. Brispirit refuses, and forces Sispirit away with a bolt of lightning,

The heroes continue on a quest against different villains from the games of X-Scissor, meeting several other heroes and antiheroes.