Titan

As most Eternals of Titan are not part of the Machine that is Earth, they do not follow the three principles and they do not get revived in the Resurrection Chamber when they die.

The Eternal of Titan are a group of Eternals who descended from the Eternals of Earth. While Eternals can reproduce in a variety of ways, nigh-none of them results in Eternals that could be integrated into the Machine that is Earth. Thus, the Eternals connected to the Machine do not consider the Eternals of Titan to be "true" Eternals.

Mentor and Sui-San, two Eternals from Earth, were trying to produce true Eternal children (i.e. able to be added to the Machine) on Titan, and with the help of Saturn, they gave birth to Mors and Amor. Amor was a success and was added to the Machine. Mors was an utter failure: he was born with Deviant syndrome, was unable to be fully incorporated into the Machine, and he ended up as a mass murderer who eventually massacred the people of Titan.

In the Titan Schism, Mentor traveled to the moon of Titan to meet Sui-San and try to unlock the secret of true Eternal reproduction, as most methods of Eternal procreation resulted in Eternals that could not be added to the Machine that is Earth. Nevertheless, they populated Titan with beings born from clones, constructs, aliens, etc. who possessed Eternal traits but were not part of the Machine. They were the Eternals of Titan.

They developed Titan into a wonder of science, building the super-computer ISAAC to help them run the environment. With time, they eventually succeeded in reproducing biologically and breeding true Eternals that can be added to the Machine with the help of the Quantum Bands, Mors and Amor. However, Mors was a genocidal mutated monster and he wiped out nearly all of the peaceful Eternals of Titan.