Kano grew up with his twin sister Kyoko in Kaze no Kuni. Their parents were wealthy elitists who used their births to further their own personal agendas, and they as children were largely discarded to be attended to by a stream of nannies who took absolute advantage of the situation and sometimes even hit or abused the children; at the bare minimum forcing them to do the housework while they lazed around. Kano was considered the troublemaker of the two, always getting himself into predicaments so as to draw the ire of their current nanny away from Kyoko and solely onto himself.
They had a clearing they always used to go to in order escape life and play when their lives permitted. A small group of nukenin came across the clearing badly injured and without chakra, and Kyoko decided to heal them. When pursuing ANBU arrived, Kano misled the ANBU while Kyoko kept them hidden, Kyoko working hard to save their lives with the first aid she'd picked up caring for her brother and herself. When the coast was clear and they were no longer in danger, Kyoko and Kano expressed a desire to learn more about being ninja. The nukenin, understanding the sweet deal they could make riding off of the coattails of these children, agreed for food and protection from hunters, to help train the children in the ways of the ninja. They trained hard during a handful of years, to the point that they became incredibly impressive, eventually even surpassing their trainers in skill. One day, as they were flowering pubescent children at the age of 13, one of them was stupid enough to try and force himself on Kyoko. Kano ended him. The others wet in defense of their friend, and Kano ended them too. While nannies had always been a threat, this was the first inkling of what dangers the outside world presented. Kano vowed to always continue growing as to be able to protect Kyoko from anything, not matter how powerful an opponent.
Realizing their own power, they outright left their home to make a home for themselves with the skills they'd learned. Kyoko was capable and intelligent, and her older brother, who to that point had always been actively protective, saw she could take care of herself and so began to get more and more relaxed and lazy rather than always trying to shelter her from everything. He still protected her, but he did not shelter her. Their wanderings led them to Sunagakure, where at the age of 16 their abilities to manipulate water was highly prized in the desert, doubly so considering Kyoko could use her water to heal others. It was here they learned first-hand the stricture of shinobi life, and Kyoko worked as a Medic, Kano by her side, assisting her where he could and picking up much of the medical trade by default in the process. A year into their stay at Sunagakure, however, something strange happened. Kyoko became possessed by an ancient spirit that predated even the religions of Sand, a spirit that called itself a goddess; the spirit that was benevolent and had joined with her to lend her its power, but in the process ended up slowly killing her. The twins left Sand peacefully to investigate Kyoko's possession. During this time Kano had become merged with a god-slaying weapon, unknown to him at first. It eventually aided them in ending Kyoko’s possession at the cost of Kano’s physical health.
Once rid of the spirit Kyoko found a disdain entirely for Kaze no Kuni, and had a hard time enjoying being within the country. So they departed the Land of Wind, becoming travelling healers much as they had before they had found Sunagakure; Kano accepting odd mercenary work to keep their heads above water metaphorically speaking, while spending every other waking moment helping his sister, who worked just as fervently to heal the sick and wounded everywhere they went, asking for nothing in return. It was during this time that Kano recovered his body’s strength, and hid the cast majority of the wear he had endured during their trials with the goddess.
Eventually, at the age of 19, the twins again found themselves at the gates of a ninja village, this time it was Kirigakure in Mizu no Kuni. Kano watched as his sister involved herself with the village’s medical wing and rolled his eyes as she did again what they had done in Wind Country. Her skills were so far above almost anything Kiri had at the time, she having devoted her entire life up until then to healing, and she so enthusiastic about the well-being of others, that the Mizukage offered her a position as a Med-nin with Kano again as her assistant. Kano didn’t fight the appointment, but promised at the first sign of a supernatural being attempting to interact with Kyoko that they were leaving.
Within a year Kyoko found herself at the rank of Med-nin Chief, already having surpassed those holding the rank at the time it was granted to her, and very quickly it became obvious she was tapped to become Medical Sennin. She showed no favor nor disdain, and was nothing but passionate about healing. Kyoko’s kind nature, enthusiastic efforts, and superhuman skill at medicine was recognized and acknowledged, and it was soon forgotten that only a few short years before they had showed up at the gates and been naturalized rather than being raised within Kiri's walls as most Mist Shinobi were.
Kyoko and Kano worked hard, Kano at the rank of Med-nin and working directly under Kyoko as her assistant, until the previous Sennin running the branch, Kendori Shuu, was terribly wounded on a very difficult mission and forced to give up leadership. Kyoko was accepted in their place, and five years after their arrival, having proven their dedication to taking care of the people of Kirigakure, Kyoko was given the title of Sennin. Over the following year she dedicated herself whole-heartedly to ensuring the branch runs smoothly and taking care of everyone she can with Kano working steadfastly as her second-in-command of the branch. Kano uses the position as a chance to reduce the work his sister has to perform, often superseding her and taking more responsibility on himself. During her village work as Sennin, he attends all meetings right alongside her as moral support and as an outside opinion since he’s not directly involved with the politics. Since taking over the Sennin position she has labored at full intensity, rarely resting or slowing down; a fact her twin has noticed and tried very hard to quell.
