Lieutenant

The Lieutenant of the Master's Army (sometimes called Lou Tenant, or Lou ) is the right hand of the Master and the commander of the Mariposa Military Base.

Background
After mutating, the Lieutenant became the model super mutant, being fast, tough, and intelligent. He was the strongest of his batch, and has always been in support of both the Unity and the Master. He firmly beliefs in the superiority of super mutants, as he considers them to be better adapted to the demands of the post-nuclear world.

Abilities
The Lieutenant has about 250 HP, is equipped with a Gatling laser. During the battle, he is aided by Van Hagan, two of his guards and some robobrains.

Quests

 * Destroy the source of the Mutants: The Lieutenant is an optional encounter on the fourth level of Mariposa. He provides information on the Master's plans and can be killed to ensure his demise. Killing him or sneaking past will allow the player to pilfer his locker, which contains the nuke key that can be used to unlock the nuclear bomb console beneath the Cathedral.

Other interactions

 * Harry will take the Vault Dweller to the Lieutenant if they allow him to. The Lou will then interrogate the Vault Dweller concerning the location of their Vault. Divulging it will lead to the player being dipped and conquest of Vault 13.
 * Sneaking up on the Lieutenant (simply coming near his room will suffice) allows the Vault Dweller to overhear a conversation between him and Van Hagan concerning their imminent discovery of Vault 13. This is worth 1500 experience points.

Death animation

 * Killing the Lieutenant will trigger a unique and violent death animation:

Appearances
The Lieutenant appears in Fallout, and Fallout 2. He is mentioned in the Fallout: New Vegas add-on Dead Money.

Behind the scenes
According to Chris Avellone, the Lieutenant potentially became more intelligent after his FEV treatment.