Information before we begin

So basically, the hashiras are demons, and the uppermoons are hashiras.

Muzan Kibutsuji is the hashira master and Kagaya Ubuyashiki is the Demon King

Nezuko is a slayer and Tanjiro is a demon

And yeah you get the idea

Nezuko was running on thick snow and icy air to get her brother help, who is injured, he was the only one who was still alive after their family was brutally murdered.

She then stumbled on the snow, her brother who became a demon, attacked her but she got out a hatchet and put it in his mouth to prevent him from eating her.

She struggled to keep Tanjiro away and pleaded for him not to give in to his demon side

Then a hashira appeared....about to kill Tanjiro.....

Also there's slight ships