Mizu-Oni: Water Demon

Disclaimer: I do not own Demon Slayer or any characters (except my OC). Those rightfully belong to the creators of said show/movies/manga. I am just a really big fan and wanted one of my "What ifs" to be placed in the world. I also do not own the pictures used for visual effects.
That being said, please do not use my oc, the 'plotline', or my idea without explicit permission.
This story is also kid-friendly/safe for work. There are no triggers (to my knowledge, if there is, please let me know). There are also no ships.
This is the main thing, you can skip the rest of the "summary" and read!

This is a one-shot story of an idea that has been floating in my mind for a while now: What if Yuichiro Tokito survived but became a demon?
This is an alternative timeline, where everything is *slightly* off-track. Muichiro Tokito is the same, remembering nothing/thinking his family died (so he doesn't know of his demon-turned-brother). Yuichiro doesn't remember his human-life, just bits and pieces that don't connect together.
This story dives into Yuichiro's mind. How he feels as a demon, his thoughts and ideas, etc. I have many more ideas similar to this, but decided that they should have their own spotlight.

Please vote and let me know if you would like me to explore this in depth or a personal request on another "what if" you might have.

By the way, this is an English Written version. This means I didn't use honorifics (such as ~san, ~chan, etc) or many Japanese words (such as big brother, sister, parents, etc). I did end up using a couple due to how they fit the story better than English ones/were easier to distinguish.

I'm sorry for the long "summary" but I hope you enjoy the one-shot!