The second youngest of the offspring in the Saiyajin family and younger of the twin brothers. Mirai's life began very differently than Omni's did. Namuh had given birth to Omni's poke-egg. Since was just hours afterwards possessed by the Parasite Demon Missingno, and with the possession, Mirai's unborn poke-egg was effected during this time, with his father managing to purify Namuh of the parasite, a piece of it remained inside Mirai's unborn body. His poke-egg being born later that day, with his hatching several months later only hours after Omni hatched, his parents unaware of the parasite's hold on their child. Negatively effecting him, once Mirai had hatched, he appeared to be normal like his older brother, however, he would show signs of sickness and health problems.

Mirai shared his older brother's carefree and pure nature, having the same natural talent to fight and enjoyed the training he recieved with his parents and older sister. But over time he would have random bursts of cruel acts, one such where he almost destroyed his older sister Nevyda's Poke-egg, and he would attempt to kill Namuh once. Such acts leaving his parents and older sister in worry and concern, Unaware of why he was having these mental acts that contradicted his nature and personality. Mirai would not long catch on to what he was doing and become fearful of the things he might cause his family. However, he was constantly assured that they loved him and would help him through this many times.

In one last event of cruelness, Mirai would attack Nevyda while she was off guard, striking her down to near-death. The cries of his older sister reaching him deep inside, and with the light of her voice, Mirai would transform into his Super Pokemon form. A form which shocked both him and Nevyda as the lingering piece of Missingno was drove out of Mirai and reformed before them. Now free of his sickness and problems, Mirai fought off the monster, unfortunately in a tragic turn of events, Mirai was killed by the creature moments before Nayias and Namuh arrived, his parents destroying the creature fully and mourning over Mirai's lost life. He was buried in a grave on the opposite end of the island, a loss that greatly and deeply effected them all for several years. Something his older brother wouldn't find out until returning from the academy 2 years later.

Soon, only hours after his burial, a Black furred female Pachirisu with a sharingan eye known as The Dark Clone, used a portal to snatch Mirai's corpse from his grave, seeing the deceased Pichu as a great potential recruit to her organization to help counter the Saiyajin family, she used her power to revive the young Pichu, initially frightened and scared, Mirai attempted to flee, but was quickly overpowered and held down by DNA who was being controlled by the dark clone. Using her sharingan genjutsu on Mirai, he was brainwashed and controlled, soon being given the identidy of Young Chaos in the ranks of Poketsuki Ultima. Mirai's personality was greatly altered due to his brainwashed state, and was now serious, calm and collected.

Over the next three years, Mirai would grow in strength in Poketsuki and achieve Super Pokemon 2 around the same time his older brother had far away, being teamed up with DNA as partners, their mission being different than jinchuriki assignments, the mission to fight off and kill any Saiyans that got in Poketsuki's way. The very first battle lead to Young Chaos and DNA coming up against Nevyda Saiyajin and Kaede Kobayashi, an event which lead to Young Chaos' indentidy being revealed during the fight, causing Nevyda great shock and mixed feelings. Surprisingly, when DNA fired off a beam to finish off the Pikachu pair, Mirai flew in and saved Kaede despite his brainwashed state, showing her and Nevyda both that he was still in his mind somewhere.

Mirai would later come up against his older brother Omni, one-on-one, the twin brothers would fight, purely equal and evenly matched. However, thanks to the help of Holly Hoshi and her unique power, Mirai's mind was purified of the brainwash and he regained his original state of mind. However, Mirai opted to remain in Poketsuki Ultima as a spy to help his family and feed information to Valor Dragoonyne and Raiou Uzumaki, a dangerous job which worked for awhile, but with the recruit of The Prototype, his job became increasingly difficult, soon bringing suspiscian to the Dark Clone over Mirai's acts. Kouki Oyadama called Mirai within the chambers, the young Pichu unaware of his fate, was soon possessed by the very same demon who ruined his birth and young life. Being controlled overshadowed and controlled by the stronger complete version of the Parasite Demon now revealing all of Mirai's secrets to The Dark Clone and Prototype.

The Possessed Pichu would go on to fight Omni again, this time without his own actions. A battle that nearly left Omni dead, with the help of Holly Hoshi, Mirai was freed of the evil parasite demon, soon reawakening to find himself with his older brother and best friend Holly Hoshi. The Pichu Trio would have little rest as Missingno attempted to possess DNA who arrived, but reversed the action and absorbed the parasite demon becoming more powerful, fighting along side Omni, the two were quickly overpowered, but thanks to the quick thinking, the two bros performed the Fusion dance and became Omnrai, Achieving the Super Pokemon 3 Transformation, DNA was defeated. Now reunited with his loving Family, Mirai enjoyed the life he wanted from the start.

He would later fight along side Omni, his father Nayias and The Prototype against the Legendary Super Saiyan Pikachu Jigoku-Ji and later fight along side his family with the anti-group to help defeat Poketsuki Ultima.