the original au is from @locatings on YouTube! (the idea of making this is my idea though)

Atsushi was sent on a long-term mission by the ADA: Infiltrate the Demon Slayer Corp as a Hashira under the alias of Tomioka Giyuu .Although nervous, Atsushi s determined to complete his mission and gather enough information about the Corps to form an alliance with them. But what will happen when all the Hashiras are put under an ability that shows them Atsushi's memories? How will they react when their fellow Water Hashira is not what they believe him to be? ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' TW: eating disorder forced cannibalism. child abuse self-harm Akutagawa and Atsushi being oblivious idiots.