The Powers That Be was a term that referred to the first beings to exist in this dimension after the schism that created them and the Old Ones. After leaving this dimension, these beings watched over mankind and guided the forces of good. In many ways, they can be seen as the good equivalent to the Senior Partners.
The Powers That Be were extremely powerful beings. Jasmine, a fallen Power, claimed that she was "forged in the inferno of creation". Jasmine was incredibly powerful despite having lost a portion of her powers after stepping down as a Power That Be. Despite their might, they were forced to leave Earth and watch from afar instead, due to the growing power of the Old Ones.
Having left Earth, The Powers That Be had the tendency to recruit significant people in the grand design to be their "champion." For example, in 1996, possibly knowing that Angel, the vampire with a soul, would eventually play a crucial part in the apocalypse, the Powers sent him a guide in the form of the benevolent demon, Whistler to set him on the path of active redemption. Later on, the Powers gave the gift of seeing visions to a half-demon named Doyle who was sent to be Angel's guide in helping the helpless. Due to the destruction of the Seed of Wonder, everything supernatural was cut off from the Earth. Because of this, it was unclear how the Powers would be able to influence this world. Whistler, who appeared to be connected with the Powers was unable to make contact with them, which he blames Angel for.