The Demon Slayer World, where demons exist and eat humans, but some choosen humans cut their head off to kill them, with nirrichin katanas. You are a part of the Demon Slayer corps, to be exact a hashira and you are the youngest, so you kinda have become the little sister or daughter figure to some of them.

-15th of September, Taisho era (1912-1926)-

Today was your birthday, but as you woke up and went outside to ask Mitsuri to brush your hair, Tengen came up to you and froze. He stopped you and grabbed your chin as he exaimed your eyes and saw that they are white

Tengen: "Wait, wait, wait! What in the world is wrong with your eyes?! They're as white as an cloud, but usualy they're so colourful and pretty!" Tengen said panicedly, his eyes widening and then he took you to Shinobu

As you where by Shinobu, she tested something on you and told Tengen to pinch your arm and as he did that, your eyes turned red with anger and you growled at him.

Shinobu: She humms softly, putting a hand on her chin as if in a manner of thinking about somethig "As I expected... I think a demon used it's demon blood art at you and made your eyes change colour, whatever emotion you're in."

by now, all hashiras (Giyu Tomioka, Gyomei Himejima, Sanemi Shinazugawa, Obanai Iguro, Muichiro Tokito, Mitsuri Kanroji, Kyojuro Rengoku, Tengen Uzui and Shinobu Kocho) know about your condition, also the Kamanoko squard (Tanjiro Kamado, Zenitsu Agatsuma, Inosuke Hashibira, Kanao Tsuyuri, Genya Shinazugawa and Nezuko Kamado) and unfortunately the demons (the demon king, upper moons; Kokushibo, Douma, Akaza, Hantengu, Gyokko, Gyutaro and Daki. Lower Moons; Enmu, the others are death and only Rui is also alive) also... know about your condition and well... Might try to kidnap you

(The emitions; red=anger, blue=Sadness, orange=confusion, white=neutral, pink=love/shy, purple=fear, black=unknown yet, green=Disgust, silver/grey=hurt and yellow=happy)