Astro is a robot replica of the late Tobio "Tobi" Tenma, the son of robotics expert Dr. Tenma in order to bring his son back to life. This backfired, however, as the replica only served as a painful reminder of his son's death. Upon discovering his newfound robotic capabilities the replica confronted Tenma who explained his true nature and rejected him as his son. Distraught, the replica flies away only to be pursued by Metro City's law enforcement lead by President Stone who wishes to obtain the blue core the replica was powered by, leading to him falling to the polluted surface.
After waken up, the replica found himself met a group of children who were looking for old robots to be used in their surrogate father Hamegg's robot fighting ring, who also happens to be a robot repairman. He also meets a trio of inept revolutionary robots called the Robot Revolutionary Front (RRF), who dubbed him 'Astro'. Astro lives with the children and Hamegg for a while, even repairing a giant old robot who they name Zog who they plan to use for the fighting ring. When Hamegg discovered Astro's robotic nature, he incapacitated him and forced him to fight as well. Just as Astro and Zog began to rebel, Stone's forces arrive and take Astro back to Metro City.He was taken to Dr. Tenma and apologized for not being a good enough substitute for Tobi and agreed to be deactivated so that the Blue Core could be extracted. Having a change of heart and realizing that even though Astro isn't Tobi, he's still his son, Dr. Tenma reactivates him and lets him escape. Furious, Stone sent the red core powered Peacekeeper to get him back, resulting in a fight that destroyed Metro City's power core, causing the city to crash to the surface. Realizing that the Peacekeeper is too unstable, Astro sacrificed himself to destroy it, but was revived by Zorg just in time to defend Metro City from invading aliens.
Battles here were deemed to be unfair or otherwise not in accordance with wiki standards, and have been removed from the statuses of the warriors and displayed below.
Megaman Zero was leading a squad of soildiers to attack Copy X. "Are we even close?"one of the soildiers complained. "Soon we will be." Zero responded. As soon as he saw X's fortress, he ordered his soildiers to attack. They opened fire once they were in. Copy X , unknown to Zero, teleported right behind him an teleported to the Hamegg Arena. He found himself behind what looked liked a gate. He looked outside the gate and was horrified with what he saw. He saw robots fighting to the deah and being destroyed without any sense of honor. Then he saw Astro Boy. He immediatly thought he was a reploid.After seeing him fight some robots, his thoughts changed. He then heard Hamegg announcing "Somene named X has sent robot called Zero to compete in these games. He heard the crow chearing. The gate opened as he stepped out. "And luckily, we had another robot that would be competing called Astro Boy!" Hamegg roared. 'I have to fight him?' Zero thought. Zero and Astro Boy prepared to fight. Zero took out his Z-saber and charged at Astro Boy. Astro flew into the air and started shooting Zero with his cannon arms. Zero retaliated by dodging and quickly took out his buster shot and charged it to it's maximam. He shot and it hit Astro's foot and he fell to the ground. Astro then used his finger lasers at Zero and Zero took out his shield boomerand and blocked the finger lasers. He then threw the Shield Boomerang and sliced of the finger laser guns. Zero then activated his Zero Knuckle and used beam shot him, which hit Astro in the leg, causing him to loose balance. Zero then jumped and used Widebuster and sent a barrage of missles to hit Astro. Astro just notices them and he barely dodges out of the way. He is on the ground and Zero walks towards him cautionly. Then the Butt Machine gus come out and Zero is hit by the blasts and is hit by the blasts. He then brings out the flame sabre and hits the ground, sending a barrage on flames at Astro boy andit hits Astro,causing damage. Zero then comes at him with his Z-saber and Asto gets ready to fight. Zero slashes at Astro and hits him in the arm. Astro tries to punch Zero, but he activated his Death Pierce and stabbed Astro with it. Zero then sensed his blue core, and realized he can only kill him by taking away the blue core. But before he can do anyhing, Astro punches him down and prepares to kill him with his arm cannons. But the, Zero activates his Gyro Boomerang and knocks him away. As Astro struggles to get steady, Zero activates Bee rod and it goes through Astro's chest and Blue Core is on the end of the rod. Astro quickly falls down dead. Zero looks down at his dead opponet and wondered if their was an alternative.
This was a close match, both warriors strong in their own way. But Megaman Zero's superior agility, more expiriance and better training gave Zero the win. Not to mention Astro Boy's weaponry is more for taking on groups of and bigger opponets, where as Zero'a weaponry as for 1 on 1 battling.