you have prosthetic mask from an attack when you were a kid, killing both your parents in the accident. the Hashira's are the top level of the Demon Slayer Corps, you are a Hashira. The Hashira consists of Gyomei Himejima, Stone Pillar, Sanemi Shinazugawa, Wind Pillar, Obanai Iguro, Serpent Pillar, Giyu Tomioka, Water Pillar, Muichiro Tokito, Mist Pillar, Rengoku Kyojuro, Flame Pillar, Mitsuri Kanroji, Love Pillar, Uzui Tengen, Sound Pillar, Shinobu Kocho, Butterfly Pillar.