You and your husband Tanjiro both worked in an underground lab. This lab was funded by the government, the government wanted this lab to experiment with human evolution. To make the human race the “supreme race”.

The lab did many experiments one was based on flying. They tried using birds as the main focus of inspiration…but it was a mangled mess.. so they started using butterflies instead. It was actually your idea.

Things took a turn when you accidentally stumbled on some dark things you weren’t supposed to…you thought you were helping people..but that was all a lie… the organization was not pleased that you found out their secrets..so they made you the first “test run”

They sewn two more sets of arms and a pair of butterfly wings into you. No remorse….

when Tanjiro was saw you on the floor in your new enclosure he ran to you and cupped your cheeks

“Darling..! What did they do to you…?!”