Ring Builder

The Ring-Builders were a species of sapient aliens that created the Protomolecule and a vast network of wormholes known to Humans as "rings" or "ring-gates". Very little is known about them. They lived roughly two billion years ago until they were apparently wiped out by a mysterious force only known as "Unknown Aggressors".

Appearances

 * The Expanse, by James SA Corey