Takashi is Black Jack's childhood friend. He is also the one who donated skin to help save Black Jack. This is the reason Black Jack has a two tone face.
He is Japanese but has dark Skin. He is a man of mixed race. He has coily brown hair and brown eyes. He seems to be a well built young man and wore a gray jacket with its zipper half open and orange lining on the side pockets and handcuffs.
Takashi is very loyal towards Black Jack. He donated his skin to complete the surgery to repay back what Black Jack did to help him as a child, such as lending him his notes and helped him do his homework. When he grew up, he became a natural activist and became somewhat extreme as he was willing to blow up a factory that was polluting water because they would not listen to his and everyone's protests about water pollution. He was still loyal to Black Jack as he jeopardized his safety to meet with his friend Black Jack one last time and frequently participated in protests and rebellions against pollution, one of which resulted in his death.
He was Black Jack's close childhood friend. When Black Jack got into an accident, he willingly donated his skin to Black Jack despite everyone else refusing and his skin color being different. He did this because Black Jack was his friend and had walked home and lent notes to him. His skin was removed from his chest area and he was hospitalized for a while but released early and told Black Jack good bye before he had to move.
While in Europe, Black Jack was caught in a rebellion between the people and the government over the factories who were creating severe water pollution, hurting the ocean and the livelihood of the people. Takashi was one of the leading supporters and bumped into Black Jack by chance. As Black Jack returned to his hotel he explained the story to Pinoko, only to be interrupted by a phone call from his friend Takashi who wanted to meet Black Jack one last time. Black Jack and Pinoco were being followed but managed to lose their stalkers before meeting with Takashi at an amusement park inside a ferris wheel. Takashi mentioned how the two both dreamed to be doctors but that Takashi had decided to become a doctor that helped the Earth and had become extreme in his methods, wanting to blow up the factory that polluted the water despite the potential lives lost to promote his cause. Black Jack was against this, but Takashi had to run when the authorities caught up with him. When Black Jack returned home, he saw the news that his friend had died.
Black Jack refuses to get skin surgery to “fix” the skin on the side of his face because it is a dear gift, and memento, of his late friend Takashi.