Your story in a Demon Slayer part 1

Diagnosis results Asuka was a simple human, but one day...Asuka saw an unknown slayer fighting a demon. After a few moments, demon was about to kill slayer, but Asuka reacted quickly, rushing towards demon and slayer, picking up the slayer's nichirin sword and thursting it right into demon's neck. While demon was shocked and distracted, slayer quickly pulled his/her sword out of demon's neck and cut demon head off.

That event made Asuka hate demons. After recovering from shock, Asuka realized that if he/she not going to do anything, something like that horrific event may happen again, and who knows if Asuka will survive the next encounter with a demon.

Asuka decided that he/she need to know more about demons and how to deal with them. Eventualy during the Asuka research, he/she met a slayer, who appeared to be a Kanao Tsuyuri. After hearing Asuka story and all the determination and zeal in Asuka voice, Kanao Tsuyuri decided that Asuka has a potential to become a slayer, so Kanao Tsuyuri offered Asuka to became his/her sensei, and of course, Asuka agreed. (Your sensei - your breathing style)

Training was tough, but Asuka determination and zeal helped him/her to endure everything that Kanao Tsuyuri made Asuka went through. At the end of the training Asuka became much stronger and ready for the Final Selection...

Final Selection was hard, really hard. But by cooperating with other slayers and maybe a bit of luck, Asuka managed to pass.
As Asuka got his/her ore for nichirin, Asuka asked it to be a...Naginata.
After Asuka got his/her nichirin weapon, it took a red color...