Originally a combatant in the Earthly wars in Olympia between the Titans - Kronos and his brother Oceanus would wage war against the monger Uranus. Though ultimately victorious in vanquishing Uranus and banishing him to the planet that now bears his name - Kronos would forever after avoid bloodshed.
Setting out to create a more harmonious Olympia dedicated to peace and harmony - Kronos would enrich his land and in time father two sons; Mentor and Zuras. As the land of the Eternals grew and thrived Kronos dedicated his time to research. A former scientist, Kronos was said to have been the victim of an accident while conducting his research on cosmic energies which would result in the death of his corporeal form . However his pysche would survive the catastrophe and manifest itself into the Cosmic empowered Eternal whom he currently represents. Kronos is now regarded as the oldest of all Eternals and the founder of the Titan civilization.
After many ages, A'lars (The Mentor) would grow weary of his brother Zuras and his like-minded approach of Uranus to all affairs. In seeking to find new ways to honor his father's teachings - Mentor would leave Olympia and seek the stars. In so doing, he was given the blessings of his father in founding Titan even going so far as to watch over the civilization in patriarch like fashion. Mentor himself would in time go on to have children - Starfox & Thanos; thus effectively becoming the grand-father of the two Titans.
Powers & Abilities
Kronos possesses a level of intelligence that ranks far above superhuman, as well as telepathy and cosmic awareness. He can evidently exert control over the souls of deceased mortals, even to the extent of using them to animate artificial bodies which he can create from inanimate matter. Kronos has also become one of the embodiments of time, and as such can exert an unknown degree of control over its flow, which he does in very subtle ways when required.
Examples of this power can be taken from the re-animation of the human known as Arthur Douglas. Following a tragic accident as a result of Thanos's early visits to planet Earth - the soul matter of Arthur Douglas was harvested and reclaimed by Kronos. Transformed by cosmic power, Arthur Douglas would be reborn into the being of Drax the Destroyer. In so doing - Kronos charged Drax with the sole task of moving through time and space to seek out Thanos for what was foreseen as the doom of Titan.
Further evidence of Kronos in deed would be found in the creation of the being known as Eon - a god like being charged with over-seeing events of great cosmic importance. To that end, Eon would empower Captain Marvel and host Rick Jones with the Power Cosmic to prevent the destruction sought by Thanos while in possession of the Cosmic Cube . These events were foretold by Kronos to Eon - who waited approximately 8 billion years in Earth time to fulfill this tasking.