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. 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. 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.)
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
SUPERMAN TAS: Apokolips Now
JUSTICE LEAGUE: Twilight