Rocksalt

 is a Raider of randomly determined gender and appearance. He/she is presumably the leader of the small section of raiders who live in the mole rat infested Tepid Sewers, where he/she can be found by the player.

He/she is hostile towards the player like the rest of the raiders, and appears to serve no purpose in the game aside from dropping Rocksalt's Key, which opens a storage room in the sewers, several containers in the storage room, and a safe in the raiders' nearby sleeping quarters.

Rocksalt is guarded by a bountiful lot of frag mines, and two or more raiders in a nearby room.

Bug
Although Rocksalt is enslavable, a bug exists where after the player puts a slave collar on him/her, he/she may run off to look for a weapon and will NOT go to Paradise Falls. (confirmed on Xbox360)

Appearances
 only appears in Fallout 3.