Seiya is a tall, slender teenage boy. He has short black hair with bangs and two longer locks on either side of his face while the back of his hair is shorter. A lock of hair sticks up from the top of his head. He has blue eyes framed by glasses with thick black frames, which he switches out for contacts during kyudo. The glasses conceal a black mole near his right eye.
Seiya is viewed as a mature, reliable, and kind character, determined to facilitate and oversee Minato's success in kyudo. However, as he himself stated in episode two, when he gets serious, he has no need for compassion.
Seiya and Minato were friends since they were very little due to being neighbors. Along with Ryohei, the three of them were kindergarten and elementary school friends and had many adventures together.
He enters Kazemai high school in their first year, following Minato, and is chosen as the student representative. Shortly after, he joins the kyudo club and becomes their president.
After the second round of the competition, Shu reveals that Seiya doesn't love archery.
Skills and Abilities Edit
Seiya has a really good academic result that he can represents the whole new incoming first form.
- Seiya has a dog named Kuma, which means "bear" in Japanese.
- His favorite food is stir fried water spinach.
- The least favorite is ratatouille, as there are many things that he dislikes in there. However, what is it exactly is a secret. 
- Seiya's hobby is watching soccer games. He enjoys collecting data and creating strategies.
- Is dog person.
- Likes mountains as he used to play together with Minato.
- If he had the chance to time-travel, he would choose to go to the past. The reason is a secret.