As a child, Ryoma was trained by his father in his family's karate style, inspiring him to follow his instincts and never cry. He eventually found the bodies of his parents after they hung themselves. Afterwards, Ryoma went through a long term depression that lasted even after the series began. Because no one could understand the suffering he had been through, Ryoma refused to conform to what people expected him to do leaving him isolated.
Ryoma is of average height and weight of a high school age teenager. He has messy black hair with black eyes that occasionally turn red when experiencing a rush.
After the death of his parents, Ryoma became very withdrawn with hardly any concern with his life and future. As a result, he does certain activities when asked to or if provoked. Because of this, he is not afraid to get violent on people who flaunt their status without any fear of what happens to him. This is not to say that he is heartless, as he had called out Dr. Saotome for talking about deaths at his school being no big deal even in spite of Hayato saying that it looked like he had no problem during the fight. Ryoma's exposure to the Saotome Institute's exploits had left him at a standstill but chooses to fight nonetheless. Yet his traumas still affected him as his decisions started to affect his performances.
With nothing to live for and refusing to accept sympathy from others, Ryoma refused contact with others becoming isolated as a result. But upon accepting his role as a Getter Pilot, Ryoma took it upon himself to fight as to show an example for others to follow. After this, Ryoma becomes more confident in himself and his teammates while still butting heads with Hayato from time to time.
Ryoma is a skilled fighter, able to pull distractions and split second maneuvers to overpower multiple opponents. Because of his strong will to overcome weakness, he is able to control the Getter Robo with the urge to destroy. His strong ties to the Getter Rays also allow very high compatibility with the Getter, able to pilot, master the controls, and time attacks with the Getter Robo on his first try.
At school, Ryoma had been reclusive with the only person making any connection to him being Michiru Saotome. When a few bullies threaten Michiru on his way home, Ryoma seems to ignore the events but later jumps in and beats them up. As one of the bullies had connections to some of the school staff, Ryoma was asked to withdraw on his own for the school to save face. When Michiru wanted to thank him for the other day, the school was attacked by mysterious monsters called the Devolved, killing everyone in Ryoma's class except him. Ryoma looked in shock at the monstrosity and is approached by Dr. Saotome, Michiru's thought to be dead father who tells Ryoma that this is only the beginning while revealing the Getter Robo to him.
Ryoma is shocked that he is asked to pilot such a machine as he had no experience beforehand. Saotome told him not worry however, stating that he will be recognized by the Getter Rays that power the robot. As the Devolved attacks, the Getter separates into its units with the Eagle unit crash landing near Ryoma. As Ryoma gets inside, he gains full knowledge of how to pilot the Getter Machine, performing the formation of Getter 1 and fighting the Devolved in a nearly one-sided battle until the Devolved being's exposure to Getter Rays caused it to change into a different form. Even then Ryoma kept fighting on unleashing the Getter Robo's Getter Beam as the Devolved started to smile and attack. With the Devolved destroyed, Ryoma was exhausted but was still standing.
At the Saotome Institute, Ryoma is formally greeted by the staff including Hayato and Musashi. Peaked with a lot of questions after what happened, Dr. Saotome shows Ryoma a Getter Ray source below the Institute called the "Fragment of the Emperor". Dr. Saotome explains that Ryoma, Hayato, and Musashi have all piloted the Getter Robo in alternate worlds and that they are all connected to the Getter Rays including the piece of the almighty Getter known as Emperor.
Ryoma goes out to the ruins of his school having some small talk with Musashi until they are attacked by Deformed cells taking over the scientists. Ryoma watches as Musashi is forced to kill the scientist until more showed up. Ryoma was shocked wondering if there was anything they could do to help. The rest of the scientists however were killed by Hayato in the Getter 2. Hayato steps out telling Ryoma to take a long look at what they face including the threat they bring.