Inotan Soulmate AU

This is my first story so it might not the best and please be nice.* I do not own any of the characters from demon slayer.*
Tanjirou lives in a world were demons exist but also were soulmates exist as well. There is a red string that is tied to your pinky finger and is attached to you soulmates. Nothing can brake this string and it can stretch across the world if need be.
Tanjirou never really cared to much about soulmates, just wanting to make sure his family was safe. And on that fateful day were his family had died and his little sister had become a demon he never thought about a soulmate again...
that is until he meat his soulmate.