Everyone who knew him knew there was something very strange about him. He didn't look all that different or act all that different, but there was just something about him. He was a slightly slender boy, but not all that skinny, and he had dark black hair that went just to his eyes. His eyes always seemed to droop a bit, making him look sickly, but besides that, there was nothing strange about his appearance. Kurosuchi was always a quiet child and preferred to not play with other children, and when he wasn't doing chores and the like he always just locked himself in his room and rarely came out. When he got older he decided to become a medical ninja. There was, at the time, a shortage of medics, and Kurosuchi seemed very exited about becoming one and helping his village. What wasn't known was what Kurosuchi was thinking when he singed up for ninja academy.
Throughout his education, Kurosuchi continued his quiet behavior. His grades were very average when it came to taijutsu and ninjutsu, but excelled in genjutsu and chakara control. He passed with high marks, and then went on to continue training with the medical staff. By his second year as a medical ninja, Kurosuchi was well known as a very talented surgeon, but there was one thing that he excelled in even greater than that, and that was autopsies. He was good at keeping people alive, but he was great when it came to working with the dead. Kurosuchi was able to tell how a person died, usually just by looking at their clothes, and he was also able to dispose of the body very quickly and cleanly.
It wasn't until Tsunade came into position of Hokage that it seemed to people that something was amiss with Kurosuchi. After looking over his file, Tsunade noticed that some records were missing. After an investigation, it was discovered that Kurosuchi had burnt the missing records in order to get into medical school. From the investigation, Tsunade learned that as a child his parents had broken into the storm cellar while he was away and found many small animals, dissected and frozen. Kurosuchi had been going out into the woods, killing the animals he could catch, dissecting and studying them, then freezing them to 'learn about them.' He had been sent to a psychologist, but stopped going to his sessions after the first month. When put into the ninja academy, his forms came from an orphanage. It was said he was found in the woods half-dead with broken ribs and a cut across the top of his forehead. His parents were never found.
From the report taken by the ANBU, explaining what evidence had been collected: his parents blood all over him, the fact that he was found with the murder weapon, and that there were no other leads, it was clear to Tsunade that Kurosuchi had killed his own parents, but because his parents' bodies were never found, it could not be determined whether he actually had or hadn't. She couldn't even put him into custody to question him. She could, however, question him about the missing files. After the questioning, Tsunade was astonished when Kurosuchi's mind only turned up blank. When asked about his past he would recall being alone all the time and 'studying' the animals, but he claimed he couldn't even remember his first session with the psychiatrist. After being interrogated, results were the same, and all that was left was to enter into his mind with the ANBU and retrieve the memories by force. The mind team and Kurosuchi were in the room for a full hour when they finally gave up. It seemed there was a large space that was just blacked out, like he wasn't even awake. Because of the lack of evidence, yet keeping in mind that he had purposefully withdrawn information from the Hokage to become a medic, Tsunade allowed Kurosuchi to stay on as a medic as long as he was under strict surveillance. Kurosuchi agreed to the terms.
After Sakura became Tsunade's new apprentice, there seemed to be no use for Kurosuchi in the healing department, so he turned his focus more and more toward autopsies and crime-scene clean-up jobs. A few years had passed and Kurosuchi was now mostly working for one particular VIP client. This client was known to make strange requests of Konoha, and even though he paid very well, Tsunade still felt that he wasn't to be completely trusted. Tsunade wanted a personal assistant to both work for and watch this client, and because over the last few years he had been able to gain some moderate trust with the Hokage, Kurosuchi was elected. Most of his duties were now devoted to cleaning-up after his 'master' and making sure only people with appointments were able to get on the premises. This was an easy job, and during the night Kurosuchi was able to study many medical books and do research for new medical jutsus. That he was also acting as a guard for the client, he was not able to leave the mansion except for weekends, but even then he was told to follow and watch the client anyway, so Kurosuchi was unable to get any real research done and he was getting really upset that he was getting so far behind in his studies.
Finally something came up, and Kurosuchi was almost able to leave this crappy assignment. While cleaning up after the clients snack at his desk, Kurosuchi found some ransom letters addressed to other people. It seemed that this client was into some pretty dirty stuff like kidnapping. After some more snooping, more and more evidence was found until Kurosuchi was able to get the OK from Tsunade to make an arrest. She of course didn't want anybody to know that Konoha had working for a kidnapper, so she asked if the client could be taken into custody very quietly. The next day, Kurosuchi and his five man team came back to Konoha with the kidnapper in tow, and when the mansion was visited next, it looked as though no one had lived there for years.