Heracles was a Jaffa and the First Prime of System Lord Zeus who appeared much like his ancestors from ancient Greece. He was an extremely muscled man with bronze, tanned skin gained from long hours of training under the sun. He, much like his master, had a full beard and hair which many of Zeus' subjects have since taken to be a fashion statement. Heracles always carried out his master's will to the letter and, although he sometimes tempers them to show his own clemency, he never dreamt of disobeying his master.
He was one of the first people to welcome Zeus back home after he escapes imprisonment on the planet Tartarus and helped his master hunt down the remainder of Jaffa on Olympus who stayed loyal to Cronus even after their 'god's' death. Zeus was known to refer to him often as 'son' although they shared no biological link, neither through host nor symbiote; because of this, he was treated as if he were Zeus' son by all of his subjects. (RPG: "Living Gods: Stargate System Lords")
Heracles was discovered by a Stargate Command team on the planet Olympus along with his master during an enormous celebration. The two appeared to be approachable, even friendly and beneficial to the team and so the team engaged in talks with the Goa'uld. (RPG: "System Lord Plot Hooks")
- Heracles on the Wikipedia.