Tomioka Giyu, one who is a quiet and simple person as a demon slayer, who joined the corps to seek justice for his sister. He is someone a who's quiet from nature, someone who is patient and known to be a nice and a beloved boy for helping others out at such a young age in his village, his calm aura has resulted in jealousy from those around his childhood age, they played with Giyu's feelings by pretending to be his friend, only for him to end up death staring at them, the kids around his age ended fearing the boy they hate after seeing him angry in silent. The way he stares at them is like an ocean which would fall on them like a tsunami. Sooner or later since he turned 11, his sister was about to get married. Giyuu was happy to see his older sister to have a future, his whole life he was raised by her, and yet he ended up taking care of her as well despite being young, even though she never asked for help, she knew that her brother wants to make sure she doesn't get herself pressured. He's just like his mother, a large sense of responsibility and remaining calm and patient. Tomioka Tsutako has never been more proud. Until a tragedy struck, the village was attacked by a demon, one who has blood stains on his hair, rainbow eyes, and a pale white skin. 15 women were killed 4 of them where absorbed and Tsutako was on the list, as Giyu witnessed her getting devoured, he tried to stop the demon but he was thrown off to the side and got stuck by a shelf crashing on him. Giyu's was left helpless as he watched her getting absorbed. As dawn arrived, alot of people were crying, over there loss, Giyu however was crying and screaming really loud that no one could comfort him, not even tsutako's boyfriend could. Everyone assumed it was a bear, but since giyu was the one who saw it was a demon he ended keeping that to himself, he knew no one else would believe it because it was known as a myth as they say it is.
Later on, giyuu ran away from his village as fast as he could because he has nowhere else to go, he kept running nonstop only for him to be found a hunter, or rather a former hunter. Urokodaki sakonji, since giyuu told him everything thing. Sakonji then took him in under his wing, he ended up training Giyu along side with a boy named Sabito. Who he was around his age. Sabito and Giyu got close, Sabito who has been training alot, but Giyu has been training the hardest, which he ends up tying with sabito within months, Sabito was more surprised to see giyu fighting while remaining extremely calm, no anger, no fear, nor hatred. This is what sabito's words about him "fighting like a true man."
Sooner enough both attended final selection, Giyu and Sabito killed every demon in the exam, sabito killed 28 while giyuu killed 32, until the final day of the selection exam, they encountered the large mutating hand demon, which sabito sacrificed his life to save giyu and someone called murata who he was close to being killed only for giyu to save him. Giyu after watching his friend died to save him, he ends up unleashing something that ended up defeating by standing still and slashing every limbs on the demon and beheads it with a blink of an eye in the end.
what remains was his hoari which giyu ends up keeping it as a memory to remember his first and only best friend.
Sooner he returns to Urokodaki, crying into him, since it was a scary experience, he lost a friend of who he truly cherished and will continue to remember him.