Kinro is the elder brother of Ginro and the son of Tetsuken and Shirogane. Originally having served as one of the guards of Ishigami Village alongside Ginro, he quickly joined Senku as a member of the Kingdom of Science, serving as part of the Power Team's Defense Division. Kinro is a muscular young man of slightly above-average height with brown hair, green eyes, a scar on his right cheek and a lock of long hair that hangs between his eyes. He often has a scowl on his face partially caused by his nearsightedness. He wears a sleeveless karate gi-like uniform with a rope belt. On his back, he wears a buckler emblazoned with the village's star pattern. After the tournament to determine the chief of Ishigami Village, Kinro begins wearing a pair of glasses to correct his nearsightedness. He also carries a katana strapped to his side after Hyoga's raid. When Yuzuriha built a fashion store, Kinro wore a modern outfit. Kinro is the stern half of the two guard brothers. He takes his job seriously and is not easily distracted. He believes in hard work and despises laziness or cheating of any form, even if for a noble cause, such as being the only one against entering more of their allies to fix the Village Games so the Kingdom of Science would win, despite them needing to win in order to cure Ruri. He's dedicated to upholding the rules, refusing Senku's entry into the village, despite him saving Kohaku's life. He maintains his principles even when a huge portion of the village gets bribed by Senku's ramen, vehemently refusing to participate in any "sorcerous" activities or try "sorcerer" food. In the village tournament, after using Suika's eyeglasses made by Senku to fight against Magma, he consults with Jasper about the mask's legality, feeling as though he unfairly cheated. Though initially suspicious of Senku, he becomes a loyal member of the Kingdom of Science, vouching for Senku to the rest of the village. This also proves that, despite his adherence to rules, he is not prejudiced towards others and is capable of seeing the good in them. Kinro's reasoning skills are a bit poor in the beginning; he refused to believe there was life outside the village aside from those banished. Plus he overlooked the fact that it would be impossible for Senku to be a banished person as he is similar in age to him and never met him before; again the rule wouldn't apply to those descended from those banished, as they didn't commit crimes towards the village. In addition, he proves that, despite being a "stick in the mud" most of the time, he is genuinely loyal to his friends and is dedicated to his duty as a guard, especially in protecting the other villagers. When Kohaku asked for his help in winning the grand bout to help her sister, he was perfectly willing to help. He also often helps Senku with his man-powered generator by utilizing his labor, though is happy when it becomes automated and he doesn't have to work himself to death on it anymore. When the village is attacked by Hyoga and his forces, he is willing to sacrifice himself by having Ginro cut the bridge that holds him and Hyoga's goons to ensure they cannot harm the village. Even when heavily injured, he immediately goes back to guard duty the next day as he feels that, as the guard, he shouldn't lay around and use his injury as an excuse to shirk his duties (though his injury was serious and definitely needed more than a day to heal). He is straight-laced to a fault and tends to act as Ginro's conscious to motivate him. Prideful to a fault, he refuses to disclose his "blurry eye disease" even though it puts him at a severe disadvantage in combat. After being frightened by Senku's soap bubbles, he claims that he was merely reacting cautiously to the unknown. He tends to react mostly stoically to most things and does his best to keep his calm at all times. Despite his serious temperament, Kinro often acts emotionally. Senku successfully bribes Kinro into letting him pass by gilding his spearhead; afterwards, Kinro shows a strong emotional attachment to the spear. He often gets annoyed and worn out by Senku's experiments at his expense. After Senku creates a generator that eases his work, Kinro is excited, despite his normal disdain for laziness. In addition, he is genuinely excited by the automobile Senku makes alongside the other guys. When Minami hinted at a possible attraction of his to Kirisame, he became nervous and could only vouch for her skill. He values less shallow qualities in a woman compared to Ginro. Kinro seems to be manipulated easily, likely due to his purity and honor. Gen Asagiri made use of this when he manipulated Kinro into eventually helping Senku power an electricity generator. As a member of the Kingdom of Science, he learns to overcome some of his stubbornness. Initially dismissing arithmetic as unnecessary and impractical for combat, he is quick to join Senku's literacy school, telling Ginro that learning to write is an increasingly important part of communication.