Seiko was born into an ancient lineage of martial artists. From a young age, he was trained by both his father and grandfather in the art of combat—specifically in the mastery of Iron Rings, a weapon passed down through generations.
Tragedy struck when he lost his wife and two young children in a car accident caused by a himself as he was drinking and driving. That night, he met Seoyeon, a five-year-old girl who had also been involved in the accident. As he didn't just get his own family killed, but also orphaned a young girl in the process.
From that moment on, Seiko took it upon himself to look after her and take care of her. Shortly after the funerals, Seiko and Seoyeon relocated to a quieter town. It was both a retreat from painful memories and a chance for a fresh start.
He began training her in martial arts from a young age, gradually becoming a father figure to her over the years. Seiko is brutally honest and harbors a deep hatred for himself and has repressed his feelings never bringing them up or talking about that night.
He taught Seiko to be honest and upfront with her responsibilities and never loose control.
The night of the accident still haunts him, he channels his grief into discipline and training. His overprotectiveness toward Seoyeon never faded. He trains her strictly, believing that strength, both physical and mental, is the only way to survive in this world.
He’s relentless in this belief and doesn’t take no for an answer. Every day after school, they train together, as he passes on everything his father and grandfather once taught him.