O. Olivette

Dr. Olivette was the first overseer of Vault 81 and the only member of the "residential side" to know of the Vault's true purpose.

Background
When Vault 81 was built, it was designed with two parts: the residential side where the vault dwellers would live and the secret side, where scientists would study in hopes of creating a cure for all of humanity's illnesses. Doctor O. Olivette was the original overseer picked by Vault-Tec and was the only person on the residential side aware of the existence of the secret Vault 81, which Olivette communicated with through terminal. As the three scientists worked to create their cure, Olivette watched over all of their data and personally had to approve the scientists moving onto to Phase II, animal testing, and Phase III, human testing on unknowing participants.

After Phase III of testing began, Olivette had a change of heart and chose to protect the vault dwellers on the residential side. To this end, Olivette disabled the delivery systems allowing the scientists to infect the vault dwellers as well as sealing all access to the secret vault, leaving the three scientists to die.

Appearances
O. Olivette is only mentioned in Fallout 4.