Musashi is a teenager with an overweight-like figure and messy black hair. He is almost always seen dressed in casual attire.
Musashi is an optimistic young man who while distressed about leaving his old life behind, decides to move forward in the fight against the Devolved. He lets no setbacks hold him back and goes in full force regardless of the consequences, whether it be the capabilities of his Getter Machine or the unfortunate events that happen around him.
Musashi was once the captain of his school's judo team, giving him great endurance as well grappling skills. His skills as a pilot are phenomenal, able to fight in a Getter Machine and use its functions without transforming into the full form, enough to defeat a Devolved in a simulation while causing said simulation to shut down.
Musashi originally lived in a mountain village with his friends and family. However, at some point he was believed to have died. He was then recruited by Dr. Saotome to pilot the Getter Robo. After training in a simulation which he causes to crash (to the chagrin of Dr. Shikishima), he visits his village in the shadows while Dr. Saotome comes to bring him back while offering Musashi more time. But Musashi heads back, accepting his fate. In the first battle against the Devolved, Musashi is impressed with Ryoma's piloting skills. After the battle, Musashi formally meets Ryoma before Dr. Saotome shows him the Saotome Institute's secret. Musashi then goes with the scientists as well as his teammates to the remains of Ryoma's school collecting samples of the Devolved. Musashi speaks with Ryoma about coming to the area until the scientists are infected by the samples. Musashi is forced to kill one of the scientists in order to defend Ryoma.