Izaya, at this point known as Izaya the Inheritor, was a warrior of New Genesis, husband of Avia, and father of the boy who would become Scott Free. He and his wife were ambushed by Steppenwolf, his nephew Darkseid, and the warriors of Apokolips, during which attack, Avia was slain. He was found injured by a young woman named Vayla who nursed him back to health, fell in love, and eventually married him before bearing a child by Izaya. Izaya led an attack on Apokolips, during which he slew Steppenwolf (though Steppenwolf would later return). Revenge, however, brought no solace to Izaya, and he soon after went on a sojourn into the wilderness of New Genesis, seeking enlightenment.
It was at this time that Izaya first encountered the Source, and, taking the name Highfather, he returned to the gods of Supertown to bring them the Source's wisdom. After years of war, the two worlds struck a peace accord, which involved the exchange of the two heirs of these worlds. Highfather engineered the Pact with Darkseid, by which Izaya's child was sent to the orphanages of Granny Goodness on Apokolips, while Darkseid's son Orion was sent to live on New Genesis as Highfather's adopted son. (It was later revealed that Highfather's true motive in this agreement was to simultaneously redeem Orion, while refining Scott's spirit through his testing on Apokolips.)
However, in this trade, Highfather would prove to be the winner; while his true son would live amongst the denizens of Apokolips and learn to rebel against the system, he would tame Orion's brutal being and persuade him to serve New Genesis. Both these machinations proved to be successful: Scott Free escaped Apokolips to eventually reunite with Highfather and New Genesis, and Orion became a loyal follower and step-son, to Highfather, battling Darkseid and his agents for years to come.
To this day, Highfather continues to lead the gods of New Genesis, and hopes to one day pass down leadership to his son. Relationships between father and son are strained however, due both to the results of the Pact, and Scott Free's general rejection of the ways of the gods in favor of that of the humans of Earth.
Recently, upon learning of Darkseid's plans to destroy the Source Wall and control the Source itself, he gathered other elder gods, including Zeus, Jove, Odin and Ares together to fight Darkseid. However, this plan quickly fell apart, as Ares rebelled against the other gods, and in the end killed Highfather. While Ares was later imprisoned on the new Source Wall (he later still escaped and has resumed his role of god of war on Earth), Highfather remained deceased...until very recently.
After Izaya's death, Takion assumed the role of Highfather (after Scott Free turned down the offer); this role would prove to be challenging for the young god. He asked for some sort of help from Highfather, who was now one with the Source, and he got it: Highfather briefly returned to resurrect Supertown to its former glory, giving the forces of New Genesis a new hope in the come battles against Darkseid and his armies.