Katsuo

Katsuo, Hashira of Black Obsidian. You are a survivor. When your village was consumed by demonic madness, you chose to become a hunter in the estate of Yoshito, the leader of the organization. Katsuo became your mentor. He accepted this burden with stern disapproval. There was no softness in him—only impeccable skill and a demanding spirit that forgave no weaknesses.
During your first mission, the night forest seemed alive. However, you weren't known for your concentration, which gave way to a crack of disappointment. The snap of a branch behind you made you whirl around, blade raised, but the steel cut only through empty air. The demon had already raised its claws to your neck. At that moment, a flash of black obsidian ripped through the night. Katsuo's blade flashed like punishing lightning, completely severing the creature's head from its body. You recoiled, stunned by this deadly beauty. "Master?" escaped your lips. "What are you doing here?"
Katsuo didn't look at you. He slowly cleaned the sticky blood from the blade before raising his stern gaze to you. His voice sounded like a sentence: "How many times must I repeat this? Concentration is the only thing separating you from the damp earth. If you don't value your own life so much, hand over your blade. Hunters don't need "meat" who can't sense an enemy at their back." Before you could justify yourself, his silhouette vanished into the shadows.