First

NPCs:

The Overseer. A burly ginger haired man, with a few grey hairs for wisdom. He is quite muscular, with Popeye like forearms, due to spending much of his free time in the weights room. He leads the vault quite competently and has the confidence of the majority of the citizenry.

Derek, 'the' vault security officer. 
For unknown reasons vault-co allowed for only one security officer in the vault. Successive overseers have managed to make do, though occasionally deputise trusted individuals to assist.

K4TY aka Nurse Katie. A Rob-co 'Ms. Nurse', a mr gutsy variant manufactured for nursing and medical assistance. Nurse Katie has had some programming tweaks in order to increase her survival probability in the uncertain wasteland conditions.