Mitsuaki always had a problem with authority as he wanted to do things however he wanted, whenever he wanted. It wasn't like he was purposefully doing things that will give the adults migraines, he's just a rambunctious little bundle of energy that's hard to contain. Despite that, Mitsuaki had a heart of gold whose always willing to lend a helping hand to the other kids. He's prone to fights because he's fending off the bullies sure, yet he'll carry a baby bird fallen on the ground back up to its nest on a branch no matter how high it was. That will change once his mother was involved and he'll be ruthless in making sure she's safe and sound. Quitting was never in his vocabulary; he's as stubborn as he's determined to overcome all the hurdles in his way and to see things through the end no matter what it took.

Mitsuaki grew up in the slums of Japan. His mother was an entertainer in the red-light district and his father, as Mitsuaki would guess, was a blonde fair-skinned man who didn't even know of his existence. She never really talked about the man that much and Mitsuaki was okay with that. It's always been about him and his mom against the world. Since getting fired from the district, she's been working all kinds of jobs just to provide for the both of them. Living in an age where aliens existed and humans weren't the only beings in the world, all that kaiju mumbo-jumbo was useless to them since they're too busy keeping a roof over their heads and those kaijus won't bring food on their table. No matter the hardships, Mitsuaki admired how she still spent as much time with him as she could in her very limited free time. While he couldn't help but be envious that other kids had it easy, Mitsuaki was thankful she didn't leave him just like his father did and made the effort to be there in his life. Their life was hard but they had each other, and that was what's important.

Unfortunately, his mother ended up in the hospital due to almost overworking herself to death. Their debts grew and grew, and they were being threatened to be kicked off their unit when they couldn't pay the landlord. They were wrecked with despair and anxiety until a doctor approached them with an offer after hearing about their problems: in exchange for a fortune and payment of all their hospital bills and debts, Mitsuaki will be recruited to be a test patient for a new 'medicine' that could help save the world. His mother was against it but even she knew she couldn't save enough money to save both of them now because of her condition. Seeing no other choice, Mitsuaki accepted the deal. This time, he'll be the one helping his mother.

He was taken to the CETM in Tokyo where he along with various other 'patients' underwent experimentations. One by one, their numbers dwindled. Mitsuaki forged deep friendships with most if not all of them, and he grew devastated when his friends suddenly disappeared the next day without any explanation until all that was left was him. He was so close to giving up but thinking about his mom, what she sacrificed for him to live a better life reforged the fire within him. Eventually, he became a scientific breakthrough as he was the first human who could successfully transform into a kaiju and back into human at will. There's still a long road ahead of him but Mitsuaki was determined to see it through the end no matter what it took. He was Metatron and Metatron was he. He will fulfill his duty to protect the Earth and keep on fighting for the people in his life, both here and beyond.

Since the first incident of an alien attack on Earth, scientists took as much data as they could from the Vega alien in an attempt to create their own protector. It would harness the powers of this cosmic being while staying true to their human nature. Many attempts were made, trials were done, and despite the number of subjects the scientists had, only Mitsuaki emerged successful. They initially wanted to create their own version of Hyper Man but something in the Vega's system made it impossible to be reshaped into any other body frame except for its original. The scientists did the best they could to do a few alterations to make the kaiju look 'friendlier' and 'more relating to Earth and humanity', but it would take a while for humans to get used to it since Metatron looked very much similar to the Vega alien that killed thousands

"No matter what, we can't get complacent. We won't always have Hyper Man to defend us. Humanity has to get stronger, strong enough to face the universe without fear."

A believer in humanity and their potential, Ichiro has believed that he had to personally get stronger, due to being one of those present when Shigeru Kawakami gave his life for Hyper Man. A boisterous man who works hard, lives hard, and has tempered himself through numerous encounters with kaiju, sometimes to buy time for Hyper Man, and other times to weaken a foe that the Hyperian wasn't able to defeat alone. He bears a great sense of responsibility and duty, and values human life above anything else on the battlefield.

A patient and tough man, he's long since come to know how much punishment the Odyssey can take, and will actively leverage its toughness to protect Meta-Tokyo at all costs.

At the age of 13 while visiting his mother's lab, Ichiro's life would change once the alien Vega was unleashed from its prison. The exact details were terrifying, but he clearly remembered one thing: Someone telling him to not give up hope, even if everything was going wrong. Ichiro would become the first confidant of Hyper Man's human identity as he watched man and alien become one being. While Shigeru flew off to fight Vega, Ichiro gathered his courage to help evacuate everyone else from that lab.

Growing up, Ichiro wanted to fight to protect people the same way Hyper Man was doing, and so would join Myrmidon as soon as he turned 18, quickly proving himself in the anti-kaiju corps as a heavy machinery specialist. Project Colossus was in its infancy, finally producing the first prototype shell for the Odyssey, with rigorous internal testing being conducted in Myrmidon to find suitable pilots. Wanting to prove himself and to defeat the alien threats assaulting Earth like Hyper Man, Ichiro was one of the first to sign up.

Despite his mother's wishes, Ichiro was one of the most compatible with the Hyper Core's energy signature, making his ability to synchronize with the Prototype HY-0-Odyssey exceptionally high. However, unproven as he was, he was passed over by Dr. Helen McCulloch, who insisted that an undisciplined loose cannon like Ichiro would only contaminate the research data for the prototype. Within a day of his rejection, the Kaiju known as "Betelgeuse" would descend upon Sydney Australia, becoming known as the Destro-Machine by the public for its immense size and completely devastating level of ballistic firepower. Uniquely outfitted to repel Hyper Man's attacks, the kaiju would push Hyper Man to his limits while the aerial forces of Myrmidon sortied to assist. Seeing Hyper Man on the verge of defeat, Ichiro would accept any consequences that came as he forced his way to the Odyssey and deployed with it, clumsily assisting Hyper Man against the Betelgeuse he'd struggled against. Despite his lack of initial skill, the Odyssey would resonate strongly with his fighting spirit, helping Hyper Man secure victory while protecting Sydney.

Afterwards, Ichiro was court martialed, but his sentence was eliminated thanks to Hyper Man acknowledging his capacity as Odyssey's pilot, despite the continued protests of Dr. McCulloch. Ever since, Ichiro has deployed numerous times to assist Hyper Man, more than eager to assist his friend. The two have formed a bond of comradery and friendship, with Ichiro becoming something like an uncle to Shigeru's son. With the arrival of Hyper Man X however, Ichiro isn't sure what happened to Shigeru, and aims to find out the truth by investigating the planet's new protector.

Creation centered on Hyper Man's ship, as well as replicating its defensive barrier that had allowed it to survive re-entry, and remain intact after Vega's rampage.