Four Kings

The Four Kings, also known as the Quad Kings, were four stars in the Grand Cluster. Named Klia, Lannu, Freo, and Selris (each for Am'sz kings), they were massive blue supergiants amongst a large population of younger red, orange, and yellow stars.

It is theorized that they are the last surviving Population I stars in the cluster, about to reach supernova. Because of their proximity to each other (roughly 4 light years), if one underwent a supernova it would trigger supernovas in the other three, thus destroying the local region of the cluster. Some main sequence stars would probably also suffer this fate if they were close enough.

Though unknown to the beings on Am'sz, they were actually part of the four star Empslu system, where they were known as Empslu Aurek, Empslu Besh, Empslu Cresh, and Empslu Desh.

Behind the scenes
In a standard deck of cards, there are four kings.