Bound to a Demon Slayer Corps Secret Identity (Crossover)

[Screenshot taken on September 23] As a half-reclusive anime fan and video creator, Asahina Osamu never imagined that he, too, was a character in a fictional world! Watching the brothers he'd spent every day with suffer one after another as their world fell apart, he had no choice but to bind himself to the System that had been with him since birth, in order to prevent the world's collapse and complete the fusion of worlds. A mysterious organization has appeared throughout Japan. Its members have neither cursed energy nor supernatural abilities, yet they can slay all manner of cursed spirits and evil beings, and even handle ability users with ease! A user of Insect Breathing who has a sweet smile but shows no mercy in a fight; an unpopular user of Water Breathing; and a cowardly, shameless user of Thunder Breathing, all of whom dispatch every threat in the blink of an eye... There is even a user of Sun Breathing who can effortlessly wipe out special-grade cursed spirits with a wave of his hand, and whom even the self-proclaimed strongest fears! They all wear the same uniform and a haori, like ancient swordsmen, displaying courage and righteousness as they save people from danger, then quietly disappear without seeking recognition. A few things to know before reading: 1. Most important! Pay attention! The Demon Slayer Corps tied to the System isn't the usual Demon Slayer Corps. This is an alternate timeline where everyone died, and the original head of the Corps never appeared! If that bothers you, don't read it. Then we'll all be happy. 2. This is a practice piece, so the story will probably have a lot of plot holes. Just consider any issues to be author-created details. 3. The cover is actually a character design from another novel. I drew an extra one, and since I'm broke, I decided to use it here. QwQ 4. This is a very standard secret identity story, so don't get your hopes up too high~ Theme: May the world be at peace, with no demons or monsters