Kiriko is a doctor who is seen as Black Jacks enemy and a complete parallel to Black Jack. Kiriko does not specialize in surgery, but Euthanasia. Essentially, he doesn't treat patients but instead, helps them to end their suffering, but with a price. Almost as hefty a fee as Black Jack’s.
Unlike his older self, Kiriko shares the same ideals as Kuroo Hazama; "to save the patient no matter how impossible." It is shown during Episode 5 of Young Black Jack, that he would go to great lengths to reach a patients, such as going so far as to parachuting out of a helicopter. He is shown to be quite humorous, amicable, and very ambitious. Brave and willing to take risks (Episode 6), he stakes more on experience than hand-down knowledge, such as using anti-coagulant in amounts more than suggested (as opposed to what Kuroo inquired from textbook-knowledge) for a bullet-wound surgery.
He develops a more cynical viewpoint of things in general, tend to be more pessimistic to the medical conditions of his "patients," and begins practicing Euthanasia. In some cases, there are patients that Black Jack manages to save, including Kiriko’s father, but Kiriko decides it would be better to end his fathers suffering. Much to his sister and Black Jacks dismay. His past of being a military doctor is often shown as the cause of him having such negative views on surgery, alongside the philosophy that "in nature, creatures die they when they have to diem and there is nothing you can do to stop it.”. He also adopts the philosophy that a painless death is a better than a painful life, and counters Black Jack's views on "fighting death until the end”. This is most clearly depicted in one of the many films in which he expressed his perspective to Black Jack in the film The Two Doctors of Darkness. It is interesting to note that he retains the pessimistic attitude on himself, as seen in the same film, asking Black Jack to abandon him when he received a gunshot wound, despite the lower chance of mortality on his part (being together with arguably the best surgeon in the world). However, he still relishes saving lives, as shown when he works together with Black Jack.
Kiriko is shown to have short hair in Episode 5 of Young Black Jack, usually seen in a military staff uniform accompanied with a helmet on his first encounter with the protagonist.
In volume 6 of Young Black Jack, he is seen with a short ponytail when he encounters a Vietnamese girl named Hoa.
Kiriko has a long white untied hair and has a pale skin. He wears an eye patch on his left eye and always walks with a grim face, just like Black Jack. He also wears a black suit with a pair of black shoes to match. Occasionally, he is shown wearing a maroon coat, pants to match, and a yellow bandana around his neck. He was always seen carrying a large suitcase which is a special device that helps Kiriko with his job to end someone's suffering life. This machine painlessly stops the patients heart and other internal organs, providing a peaceful and pleasurable death on demand. Pinoko mistakes Dr. Kiriko for Black Jack in several occasions.
Before he became a “doctor of death“, he used to work as a military doctor. He saw that many of his patients had no chance of surviving and were begging for death, thus he decided to help them die in peace by lethal injection.
He works as the “doctor of death”, travelling to any parts of the world, helping people to end their suffering.