A shinobi from the village hidden in the leaves, Shiki was born from a samurai hailing from the Land of Iron, who met and fell in love with a kunoichi from Konohagakure in one of his ventures.
Shiki looks up to his father. As such, Shiki followed his footsteps and aims to become a skilled swordsman, which resulted in him spending most of his time on the art of the sword and not having enough time to learn essential shinobi skills such as Ninjutsu. Because of this, other children usually mocked Shiki for not being able to perform flashy Ninjutsu, but Shiki just ignored them and continued to swing his sword every single day.
Shiki is patient and calm, which can be seen with his daily routine of swinging his sword 500 times every day without fail, but when angered, which usually does not happen, Shiki becomes cold and aggressive. Shiki dislikes this part of him and tries to keep calm at all times.
Even though he seems to not care about learning Ninjutsu, he still wishes to be skilled with Ninjutsu so he can incorporate it along with his swordsmanship. Though, as of right now, he still isn't very good at it.
After spending a couple of years in the academy, Shiki finally graduated, and was eager to start his first official mission as a ninja of the Leaf Village, where he was tasked to find a missing cat. Shiki was a little bit disappointed, but he understood well that helping his fellow villagers is one of the important things to do as a ninja. He traveled outside of the Leaf village, into the forests, and encountered the missing cat being surrounded by a pack of hungry wolves. After seeing the scenario before him, Shiki immediately sprung into action without any hesitation. With his wooden sword in hand, he fought against the pack with great vigor and managed to fend the wolves away, suffering a few injuries in the process.
After returning the cat to it's original owner, Shiki collected his reward, and decided to treat himself to some ramen for a job well done, and continued to do missions each passing day.
One day, Shiki received a C-ranked mission, the task was to deliver an important message through a scroll to the Daimyo of the Land of Fire. After a month of finding cats, fighting packs of wolves, finding lost children and hunting spiders and larvae for medicine supplies, this was a change, and Shiki was certainly excited. He carried his trusty sword, checked his supplies, and started to travel to Tanzaku Quarters, where the Daimyo resides.
After a few hours, Shiki was halfway to Tanzaku Quarters when he encountered a masked swordsman with red hair, their forehead protector wasn't visible so Shiki assumed that he was a rogue, as the swordsman walked toward Shiki, he immediately drew his sword, but before he could do that, the swordsman moved behind Shiki at high speed and knocked him out with the blunt edge of his sword.
When he woke up, he was already lying on a hospital bed. He was apparently found in the middle of the road by a shinobi in patrol. Shiki asked what happened to the scroll but the shinobi didn't saw any scroll where he was knocked out. Disappointed, he went home to find his Father waiting for him. It seemed he had heard the news about his failure, Shiki, with tears on his eyes, expected his father to get mad, but he didn't. His father simply threw a wooden sword at him and invited him to spar in their dojo, which continued for a very long time.