Pentagram

Thea Ransome laid out on a pentagram as part of a ritual. (TV: Image of the Fendahl)

A pentagram was the symbol of a five-pointed star. It was often associated with evil in certain Earth religions.

The skull of a Fendahl Core bore a pentagram, seen by x-ray, that was a neural circuit within which it held an enormous energy reserve. Thea Ransome was later transformed into the new Core by being drugged and placed on a pentagram, from which she arose dressed in beige robes with golden skin. (TV: Image of the Fendahl)

The Scourge could possess people, existing within them as a burn mark on their hands in the shape of a pentagram. They referred to this as "the shadow" and resented people touching it. (AUDIO: The Shadow of the Scourge)