Aphelion

"First it shimmered... then it crawled... then it screamed."

- Shuro Chi, quoting the last words of an unnamed Techeun killed by the Aphelion.

The Aphelion is an entity or race of entities known to the Awoken.

Overview
Very little has been revealed about the nature of the Aphelion, but it has been stated that they are extremely dangerous, malevolent and stealthy. They have claimed the lives of many Awoken, including the inhabitants of the Reef space station Amestris, three Techeuns, and possibly the Queen's Wrath Sjur Eido.

Paladin Pavel Nolg reported seeing a "glowing creature" on the exterior of his ship Retribution shortly before executing an NLS jump; this sighting was filed along with the Amestris incident as being related to the Aphelion.

They appear to be extremely radioactive, a trait which apparently led one Awoken on the Amestris to draw a connection between the Aphelion and an apocryphal story about the fissioneers of the Distributary.

The Lost Sector known as Aphelion's Rest presumably has some connection to the Aphelion.

Trivia

 * The term "aphelion" denotes the point in which an orbiting body is farthest from the star which it orbits. As such, the use of this term to name the Aphelion may suggest that it is an entity far removed from the Light, and closely aligned (or perhaps even synonymous) with the Darkness.