Some Erin hcs that have been stuck in draft hell for years now :p
Her birth name is Ariel - she adopted the name Erin later in life.
She was born in Cyric and is descended from the last of the Keepers.
Her ancestors were entrusted with the seal to the Keeper library in an effort to protect the secrets hidden there. It became a family heirloom, passed down from parent to child. However her mother fled the City with the seal as a young woman - supposedly she was trying to spite her family when she stole it; if she kept it, it was because she failed to pawn it off.
Erin's relationship with her parents was complicated; they had her more out of obligation than real desire. It was just the expected thing to do and she was by no means an easy baby.
Her relationship with her father was rocky and inconsistent; he taught her practical skills but he had abusive tendencies. Some days he could almost be a normal father who enjoyed teaching his daughter new things. Most days he was disinterested in her at best, outright abusive at worst.
Her mother tended to be emotionally distant and struggled to connect with her daughter at times due to depression. She never told her daughter anything about the Keepers or their lineage, and often spouted morose comments on the nature of her life, and how death would be preferable.
One night, her father beat her mother to the brink of death - Erin murdered him in an effort to protect her, which was the first seed of her murderous habits.
Her mother told her to escape Cyric before she could be arrested, and specifically told her to find her way to the City with the seal - her injuries had her confused and disoriented, so she wasn't able to properly elaborate why she should go there.
Erin had no real understanding of the significance of the City or her heritage - she just figured it had to be safer for her there if that was where her mother told her to go. She took what valuables she could find, such as her mother's necklace, and stowed away aboard a ship. She was only eight.
Her father's abuse and eventual fate was the source of her violent side - killing became a means of safety and control, and made her feel more powerful.
She came into Xiao's care during her first few months on the street and was given the name Primrose.
Unlike in canon, she killed a customer during her time as a Petal when she was about thirteen. He'd attempted to assault her and so she murdered him with a knife she'd stolen from the kitchens which she'd done to feel safer around the clients. She fled the House to avoid the consequences.
She went to Basso for help purely because he was the only person she actually knew in the City outside of the House of Blossoms. She discarded the names Ariel and Primrose to shake off any potential connection that Xiao might use to find her, and instead chose the name Erin for herself.
Garrett let her live in the Clocktower during the early years of her apprenticeship. It took her a while to choose to sleep anywhere but the rafters.
She moved into the Mill when she got to about sixteen and wanted more privacy. She'd been eyeing it for a while and figured it was perfect.
Her relationship with Garrett was probably the most stable and consistent relationship she'd ever had though it took her time to realise that his temper wasn't changeable like her father's. She began to view him as family, but as a big brother as opposed to a father figure given her negative experiences with fathers.
It was her exposure to the Primal that revealed the secrets of her heritage and the City's nature to her.