Bright Brotherhood

 is a devout religous faction, made up almost completely of Ghouls. Led by Jason Bright, they hope to take a "Great Journey" away from the Mojave Wasteland.

Background
The Bright Brotherhood are a group of ghouls who are sick of being looked down on by humanity on the whole and want to create a new life for all ghouls in space, even if they are feral. They intend to use the rockets at the REPCONN Test Site facility in the Mojave Wasteland near Novac to begin their "Great Journey."

Interactions with the player character
They appear during the quest Come Fly With Me. Their leader, Jason Bright, believes the Courier to be sent by 'the Creator' to stop "demons" and allow them to continue with the "Great Journey."

Many robed corpses of Bright followers can be found strewn across the Mojave Wasteland, such as at Primm Pass, East of Primm, and the Coyote Den, north of Nipton (probably as a feast for the Coyote Mother's young). These bodies appear from the beginning of the game, implying that these Bright followers died prior to their "Great Journey."

After the game is finished and the Courier didn't side with the Legion it says that some of the Bright brother hood came to help rebuild Novac after it took damage from the legion, implying some of them survived the rocket trip and didn't actually fly too far.

Behind the scenes
The Bright Brotherhood are a partial parody of the Covenant from the Halo series of X-Box games. The Covenant are an evil religious organization of aliens whose goal is to activate the titular "Halo" space station rings, which they believe will send them on a "Great Journey" to godhood, but in actuality would just blow up the universe. The Covenant use the term "Demon" to refer to the SPARTANs, a group of cyborg super-soldiers whom the main character, Master Chief, is one of the last surviving members of.

In addition to these two terms, the Bright Brotherhood and the Covenant share the goal of activating a space travel-related device which they believe will take them to a better place but really would just kill them all. However while it is a known fact that the function of the Halo rings is to kill all life in the galaxy, the fate of the Brotherhood upon their "successful" launch is left ambiguous despite all common sense and the laws of physics pointing to them crashing, unless they were indeed being assisted somehow by some supernatural force...

Appearances
The Bright Brotherhood appears in Fallout: New Vegas.