Madeline Shortman -- otherwise informally Maddie Shortman -- is the second-youngest child in the Shortman family. She is a 28 year old Operative Engineer working for the Alliance Military.
Relationship-wise, Maddie is very close to her younger sister and is often the voice of reason whenever Lee sets about to do something that could permanently change her life -- tattoos, gold teeth, etc. --, but is otherwise very lenient on what her younger sister chooses to do. She is one of the more intimately-connected siblings according to Lee, usually lounging on the sofa with her little sister lying on top of her or being used as a cushion to lean on.
She is also described as very selfish, however, that she will only do favors for those who do/owe her a favor in return, often making her out hard to work with but otherwise easy to adapt to being assigned different stations or groups in various cycles depending on the missions and the requirements.
Appearance-wise, Maddie is known for her various "ugly sweaters" and dark, baggy cargo pants. Another feature to find her by are the obvious and bluntly dark brown streaks in her hair that greatly contrast against her naturally blonde hair -- a tribute to her sister for bringing total independence from their parents.