A green glowing crystal sphere that was created secretly by Hephaistos at the behest of Zeus.  It was created as a repository of the souls and power of the Olympian Gods upon their deaths.  Zeus foresaw that their power would eventually fade and that Kronos would attempt to reclaim the Throne of Olympus.  He saw their murder and realizing there was no way to prevent it, clandestinely laid out a plan to prevent the resurrection of Kronos by engendering a new generation of Olympians with the Eye of Elysium.

On their deaths the souls of the Olympians would find their way to the sphere and reside there until a new generation of gods is chosen and their might is imparted upon their replacement.

Kronos by his spies on Olympus finds out about the sphere and commands his minions Tantalus and Ixion, freed from Tartarus to have it stolen.  Kronos plans to imbue himself with the might of all 12 Olympian Gods, and thus regain his freedom and his throne.

These villians then hire Brutus Starslayer to steal the Eye of Elysium being hidden in the Pindus Mountains forge of Hephaistos behind a false wall.

The eye appears as a grapefruit sized translucent green crystal sphere which radiates light.