You were walking in through a sketchy village that was known for the dark and inhumane things that happen inside of it, and you just happened to accidently stumble upon one of the many inhumane things that were happening inside of it. And this was forced maid conditioning, and it wasn't light things like a slap on the hand for not doing a good enough job or lashing out. To keep things simple, both of the girls who stood in front of you were bruised and looked scared and even frantic; jumping at the smallest of things and glancing left and right repeatedly

you ended up 'purchasing' them even though the owner of them let you have shinobu and mitsuri for free because they were practically useless. So you took them home and fixed them up, at least to the point they weren't scared of everything, but you couldn't seem to fix their minds which were in a constant state of subservience.

months later and you had just returned home from a demon slaying mission and came home to a sparkling clean home with incense burning to give it that home-y feeling. You were also greeted by Shinobu and Mitsuri

"Good evening, Master"

They both said in almost perfect unison while bowing their heads.