Serizawa was born in the Hiyosai Provine of the nation fo Minkai, within its titular city fo Hiyosai. He was the first and only son of a fellow samurai and as such was expected to follow in his fathers footsteps. Serizawa tooks this duty very seriously and at even a young age he was already uptight regarding orders, traditions, and duty.

Serizawa was taught to honor and worship Shizuru as apart of his weapon training and alongside his devotion he was tasked with upholding her edicts which included honoring his fellow samurai ancestors and upholding his training with his weaponry. Being from the city of Hiyosai, the local ruins and sea were infested with a beast known as siyokoy, and the samurai of the city were tasked with training specifically to counter these dangerous threats.

Per tradition polearms were the weapon of choice for Hiyosai samurai, and Serizawa took up the Naginata. While a Naginata was in fact a polearm, the weapon carried extra superstitions in the region as the sacred weapon of the patron oni god Fumeiyoshi, and Serizawa's affinity for the weapon as well as his armors color earned him the nickname of 'The Red Oni.' As Serizawa served his fellow samurai, he was eventually gifted a custom shoulder guard designed to reflect that nickname. While Serizawa may act to dislike the nickname, he secretly does enjoy how cool it makes him sound and he treasures his gift immensly.

While much of the other samurai of Hiyosai followed Shizuru and other deities, none took their worship as seriously as Serizawa and his father. When it came for his father to retire, as age had began to deteriorate his ability, Serizawa took up the family name and mantle as the opperative man of the home and with this newfoud initiative he took an oath under the banner of Shizuru, becoming a Paladin for her cause.

Now as a Paladin, Serizawa's resonsibilites changed somewhat and his duties fell beyond dealing with abberant eels of the coast of Hiyosai. This is not to say he grew past the need to perform 'mundane' work, but rather with the current force of samurai he was uneeded and his was offered the chance to pursue other tasks. Serizawa took the oppurtunity to travel, offering his blade to a larger swathe of people than those merely in Hiyosai and all the while devoting his service in the name of Shizuru