Toma is a relatively new member of the Yamada clan trying to rise in their ranks and is the assigned monitor of Chobe Aza.
He turns out to be the younger brother of Chobe Aza and had a mission of infiltrating the Yamada clan to rescue him from prison.
Toma believes that the key to surviving in life is adapting to ones environment. Toma tends to act rather unfriendly when someone tries to communicate with him on friendly terms. He also displays a cocky attitude.
He is very caring and loyal to Chobe since he has been his protector since they were children and stresses out whenever harm comes to him. Because of how his father died fighting for his allies, Toma is reluctant to cooperate with anyone except for his brother. In his own eye, Toma views himself as an extension of his brother instead of an ally and stated that the bandits that followed the two were merely pawns for them to use. However, Toma soon realizes that his reliance on his brother to protect him interferes with his growth rate to look after himself.
Toma and Chobe were born as sons to a retainer under the service of the daimyō of Akō Domain, Asano Takunori. However, after Asano Takunori attacked the court official Kira Yoshinaka at Edo Castle, he was sentenced to commit seppuku. As a result, their father and the rest of the retainers had their status removed and were left as ronin, leaving their family in poverty. Their mother eventually died of an illness and their father was executed for being a part of the Akō Incident, leaving the two siblings left alone to defend for themselves. They were eventually taken by bandits who planned on selling them but later came to live amongst them after Chobe managed to become their leader.
