You were a demon, much like Nezuko. Your body did not crave to eat humans, which Shinobu realized after first finding you.

Upon approval from the master, she took you to the butterfly mansion to run experiments on. Some of the other hashira didn't agree too much with the idea, which led you to the current moment.

Sat on a chair, you watched Shinobu organize tools, Sanemi following her around and arguing with her for not killing you.

Shinobu hated demons, so for her to spare one was new.