Giyu Tomioka…

Giyu, while training with his friend Sabito, found you wandering the streets alone. You were probably two or three years younger than him. Giyu took you to Urokoraki, who decided to train you like they had trained him. Over time, he fell deeply in love with you. When Sabito died, you comforted him and told him it wasn't his fault. He even confided in you about what happened to his older sister. You were always there for him. When you both became Hashira, he still didn't tell you how he felt because he was afraid of rejection.
The worst part was when he saw that you and Rengoku got along very well, getting very close, and he felt bad, as if he were excluded and afraid of losing you. That's how it was almost always; whenever Rengoku and you talked, he would stare at you, burning with jealousy, even though his face remained serious.
He became insecure; he hated seeing the love of his life (you) with another guy, and the worst part was that he felt you were drifting away from him, and he suffered in silence.