first x reader hopefully I get his personality right :0 also you are the ultimate artist

In the final battle against Muzan, Tanjiro had put his life on the line for his comrades and the innocents. In the midst of chaos, Muzan was defeated but at what cost? What if Tanjiro survived and became the demon king? This is the story not for the faint hearted. Disclaimer: "I don't own Demon slayer in any way or form."

What if Hisashi Midoriya is All For One? What if he was actually a decent dad? What if he gave up crime in order to protect the family he loves so much? And what if All Might thinks he's in hiding to build a new army? Crazy dysfunctional family shenanigans and anxious paranoid heroes await you! - Based on my Dad For One one-shot -

Kokushibo envied his brother. He envied Yoriichi until the day the man died of old age. He envied and loathed Yoriichi Tsugikuni. After Yoriichi's death, Kokushibo's life was... better. He grew stronger, like he wanted to. He buried the memories of his brother in the depts of his mind. However, those memories are brought back up when he encounters a young Demon Slayer, who resembles Yoriichi too much. ------------ Tanjirou Kamado never expected to encounter Upper Moon 1 on his mission. And he also never expected for this to be his fate. Life is an unpredictable game, and he is only one of the players. (This is a rewrite of a crappy old book which I have now deleted. This idea was inspired by this fanfic on Ao3: https://archiveofourown.org/works/47640022 PLEASE go read it)

In this story, Tanjiro wasn't able to become a human after the fight against muzan and becomes the new king of demons. Now in the modern era, tanjiro is attempting to create a serum using his blood to make his demons walk under the sun. But he discovers the new hashiras of the now demon slayer are the same hashiras he met in the past. And that is when he gets worried, because he remembers their strength. But using whats left of his humanity to create a drug that will weaken him so much giving the slayers a chance to kill him. But most of his humanity is now gone. The now modern hashiras remember their past lives and nezuko, Zenitsu, and inoskue remember their past lives.