Brotherhood of the Immanent Flesh
The Brotherhood of the Immanent Flesh was a secret organisation of people with psychic abilities lead by the Grandmaster. Their teachings were that the essense of flesh, of protoplasm, was upheld by a power, force or potential permanently pervading the universe; to embrace such an idea was to live life like art itself.
The Brotherhood had acquired alien technology over the years and used it to create a null envelope or psychic dead-zone. The Brotherhood in the future sent the reactivation signal that awoke the N-Form operating in the Quadrent and at least one other, an N-Form destroyed the Quoth homeworld. (NA: The Death of Art)
The Brotherhood was still active in 1987. Dr Greco worked for the Brotherhood investigating Gabriel Tyler and his psychic powers. The Brotherhood stole UNIT file Quadrant27787/Doctor in December 1999. (NA: Damaged Goods)
The Brotherhood was still active in 2981. It took control of the Nexus on Mimas, planning to activate psychic abilities in everyone in the solar system. It believed that the Doctor could help them control the Nexus. It was run by the new Grandmaster, a gestalt of twenty-eight telepaths that has existed for a considerable length of time; when any of the twenty-eight bodies died, the gestalt recruited a new one. The Brotherhood realized that it needed to become proactive when the N-Form tried to wipe out psis on Earth in 1987. (NA: So Vile a Sin)