Sidney

Her name is silly I know shhhhhhhhhh

Yes, she was named after Cinderella it's complicated :')

That's blood on her coat thingy but it's her brother Percy's it was his but he died so she took it

She's a little thief who started off only stealing things she needed because her stepmom is neglectful but started stealing other things, mainly for her older brother Percy who was going through some tough times and needed support. He didn't like accepting things from her, since he disapproved of her stealing, but ended up doing it anyway.

After Percy died, she tried to steal a necklace that he had wanted in his honor and got caught, so she ran away with Percy's boyfriend and joined a group of runaway and orphaned children creatively placeholder named "The Children".