The Hidden Hashira's Arc (Demon slayer au)

"Read description to understand"

One day a Kasugai Crow saw a suspicious man running with what seemed to be a bag filled with Hashira Clothing except it had diamond colored buttons heading straight to a forest going South. The Kasugai Crow decided to follow the man as the crow saw him heading straight to what seemed to be a gate but nothing behind it. The man knocked on the gate in a pattern, as the gate opened the man went in disappearing. This grabbed the Kasugai Crows attention as it followed the man quietly. It seemed to be a village hidden from everyone, the crow flew around finding ore Kasugai Crows around with what seemed to be a huge village. As the crow was flying around it saw the man again giving what seemed to be a girl with black hair with purple eyes the uniforms. The man quickly ran back to the gate as he still hasn't noticed the Kasugai Crow following him from behind, as the gate opened again when the knocking pattern was done the Kasugai Crow immediately flew going to the Hashira Mansion where Ubuyashiki was.

In this AU
Tengen never retired
And
Rengoku never died but had his arm and legs broken which is still currently healing