A Civil War between the two races then drove the Quintessons to extinction, however, it is theorised that there may be some still left behind, living in hiding for thousands of years due to their infinite lifespan. Like the Cybertronians, they are a mechanical race that has no need of food, sleep or light.
From what has been found from Quintesson ruins, Historians have been able to determine that the Quintessons were a cruel race with no morals or judgement. They staged mock court trials for randomly selected victims and force them into a guilty verdict. If they are declared innocent then they are executed for being guilty of innocence. The Quintessons have only five traits - Wrath, War, Death, Wisdom and Judgement. There are only five faces in Quintesson society, and each one corresponds to one of these traits.