The Disciples of the Thirteen are... disciples of the Thirteen.
The Disciples of the Thirteen were an ancient group that lived on Cybertron in the same age as the Patterners. These two factions would debate over the origins of legendary relic known as the Dark Spark. One side argued that it was the Spark of Unicron himself whilst the other believed it to be the ejected corruption from the Well of All Sparks. During this endless argument, the Crystal Guardians witnessed the power of the dark artifact and decided to take action where they believed it needed to remain hidden forever. Shockwave and Sharpshot encountered a recording mentioning the Disciples in an underground vault during their search for the Dark Spark.