Hervoken

The Hervoken are a race of creatures from an unnamed planet that existed million of years ago. Their technology, best described as resembling magic, gave them the ability to control matter, and alter both perception and time. For example, they have the ability to make inanimate objects take on a form of life - or, more precisely, movement and other actions that suit the Hervoken's needs.

Physical Description
The Hervoken are approximately ten feet tall, with an extremely thin body but a colossal head that somewhat resembles a Halloween pumpkin. Their hands are about as long from the wrist to the fingertips as a human arm, and their fingers have several joints (it is implied that they have more finger joints than a human) and a talon at the end. Hervoken do not seem to have legs, instead, they are said to 'drift', which implies that the species is permanently airborne. Because of their incredibly slight frame, the Hervoken are physically weak and will use 'agents' (animated or changed objects) to do their physical labour for them. The Hervoken seem to be animals rather than plants, there is some ambiguity on the matter, as they seem to use plant-like objects in their spaceships. The Hervoken are shown to have a stong bond with their technology, as is shown on several occasions when their technology is damaged, as they seem to feel pain when that occurs (even to the point of dying when it is destroyed).

Technology
Hervoken technology seems to be very much based on organic structures. The inside of Hervoken spaceships is covered in vines that seem to act as the equivalent of power cables, but have been shown to attack intruders to the ship. Hervoken technology is powered by both negative psychic energy (pain, distress, terror, etc) and flesh, of any species - so, in effect, their spaceships and other devices eat creatures if they are running low on fuel. Each Hervoken spaceship is equipped with a book, called a Necris, which acts as the starter motor for the ship. It seems to be responsible for channeling energy around the ship, but how it functions beyond that has not yet been made clear.

History
Millions of years ago, the Hervoken, who normally kept themselves to themselves, became involved in a war with the Carrionites. The details of this war are vague, but it is implied to have been very destructive, as the Eternals were forced to step in and banish both races before the universe was destroyed.

One Hervoken ship crashed on Earth, where it lay dormant for many years, during which time the town of Blackwood Falls was built on top of it. When the Hervoken were reawakened in the early 21st century, they planned to repower their ship with energy from the town's inhabitants during the upcoming Halloween celebration. The launch of the ship would have devastated the town and most of the surrounding area, but the Hervoken were defeated by the Doctor and Martha Jones. (TDA: Forever Autumn)