Humility

Case File
Millicent Greenwood's origins aren't merely obscure, they're actively covered under the Official Secrets Act. She was almost certainly recruited to the MoE straight out of University, but three years later was caught in the vaults and charged with trespass and theft of Government property.

Doctor Blaise offered her a simple choice: Spend the rest of her life in jail, or join Project Salgia as an apprentice. Her interest piqued, Millie joined the project and found herself taken into the guardianship of Pride.

The two women bonded over a mutual love of the finer things in life, and Millie took the handle Humility partially in tribute to her mentor. Humility would probably be far less impressed if she knew that Pride had arranged that

a) any secrets Humility manages to steal are gently erased from her memory by Sloth every night, and that

b) the bracelet Industry gave her contains a small hypersonic emitter that only the Angels can hear.

Abilities
Humility can avoid the perception of most living things. No matter what she does or looks like, no human and most animals (cats can see her just fine, they simply don't care that much) can hear, see, feel or smell her. The only reason she's ever caught is that she shows up on CCTV and can be percieved by machines.