Kimetsu no Yaiba : Butterfly effect

Tanjiro had always been a helper through and through.
As the eldest son he served his family and as a demon slayer he helped the Ubayashiki family.
Even as a demon slayer he helped demons find peace.
But what if due to one minor change in the cannon verse Tanjiro ended up helping the king of Demons himself ?

( No.
This is not a Mutan fic, that's nasty.)

The cover art was made by @Kubiochite, if asked it will be changed/ Deleted.