[Demon Slayer] Thanks, Becoming a Hashira Comes with a Partner

This is the autobiography of the successful woman Kamizuki Rikka. So, Ms. Kamizuki, here's a question for you: When you were young, you became the Sound Hashira's Tsuguko, rose through the ranks under his tutelage to become a Hashira, and even managed to snag a handsome man who likes to shout about five ants as your husband. What's your secret? "Obviously, it's all thanks to my own dazzling talent and gifts. And you have to make a dazzling entrance every single time!" Kamizuki Rikka answered. "Of course, even if I tell you my secret, it won't do you any good. The dazzling achievements I've accomplished aren't something an ordinary person could even dream of!" * In short, this is the story of a chuunibyou, self-confident, dazzling girl making her mark in the Demon Slayer Corps, and of two little suns warming each other. I wrote this for myself after reading an Owl x You story (what a bizarre kink), so I went all in on imagining myself with Big Bro and started writing on a whim. Please note: 1. There is original plot, and the author has changed the original author's ending, where Big Bro dies and the Sound Hashira is left disabled. The sweet moments and battle scenes are in a 1:2 ratio. Romance and career ambitions both charge ahead. This will most likely be split into two parts. I'll start the second part after I finish reading the manga. 2. The heroine is childish, extremely chuunibyou, and carefree, but trust me, she's still very reliable when trouble arises! If you really can't handle it, leave now. I'll love and cherish my daughter (not). P.S. "Dazzling" is the heroine's catchphrase, just like Tengen Uzui's "flashy." It's not a typo, and it doesn't mean the author has poor cultural knowledge or a limited vocabulary and picked the wrong adjective! This is emphasized! 3. This isn't a typical Mary Sue story. The heroine is already a Hashira when she appears, but that doesn't mean she has great talent, learned everything effortlessly, or became incredibly strong without hardship. Her only golden finger is that Big Bro falls in love with her. She's not the strongest fighter, and still has to suffer beatings alongside Big Bro the Owl (not). If you want to see the heroine beat everyone up, this isn't for you. Theme: Fighting the demons