Ghosty

The "Ghosties" were a species of aliens who came to Earth as refugees in the 21st century.

The Ghosties could be identified by their pale skin, hence their name. They had no T cells and had different blood biochemistry. Despite this, they were genetically compatible with humans.

The Ghosties were forced to leave their home planet when it became threatened by solar flares. They created a fleet of spaceships, one of which landed in Cardiff in the 21st century. This ship held 13 refugees, who were able to live quietly — initially unnoticed — among the humans, some taking human spouses. At some point, they were discovered and anti-alien prejudice became both commonplace and violent. Freda's mother and grandmother were both Ghosties. (AUDIO: Asylum)

Behind the scenes
The true name of the Ghosties is unknown. Ghosties seems to be used as a derogatory term.