Khoronos appears as a thin, pale skinned human male with long white hair and beard. He generally dresses in long, white, featureless robes.
He usually carries an hourglass in one of his hands, as a sort of badge of office.
He was born in the old civilization of Blackmoor on the planet Mystara. He discovered time travel, as one of the preeminent scientists of his day. Travelling forward in time, he was horrified to observe the nuclear holocaust that destroyed Blackmoor and shifted the axis of his home planet.
He attained immortality through the process of saving his own family from the destruction, transplanting them to various space-stations and moons throughout the system and protecting them over generations from the dangers that threatened to destroy them. He now knows that he sponsored himself through this process, by sending vital information and tools back to himself from his own distant future.
Once firmly established in his own immortality, Khoronos traveled back into the dim pre-history of Mystara to help create and organize the Hierarchy of the Spheres. He served as the first Chief Hierarch of the The Sphere of Time; an office he has held at lest three times in the intervening millennia.