Helios is the Titan that embodies the Sun. He never physically appeared in the series, but the Colossus of Rhodes appeared in Hercules and the Hero of Athens. He was the Sun God but later passed on and left his duty to Apollo.
Although his name is never mentioned, it is possible that this god, seen briefly in the film on Mount Olympus, is a caricature of Helios, the Titan god of the sun. He has sun-shaped hair, which makes him easy to identify as Helios.