Daemons

A Chaos Daemon, or simply Daemon (pronounced DEE-mahn), also known as a “Neverborn” amongst the forces of Chaos, is an intelligent and usually malevolent entity of the Warp comprised of purely psychic energy. Daemons are sentient embodiments of Chaos and collectively the greatest servants of the Chaos Gods and of Chaos itself as a universal force. Daemons are created at the whim of one of the four major Chaos Gods from a fraction of the god’s own power within the Immaterium and act as an extension of its will. A Daemon’s appearance and intrinsic character reflect the god’s own nature. These Daemons may be reabsorbed into the god’s psychic signature in the Warp at their whim.

Source