But, Kurumada will intend in the future, make a Zeus chapter of the series, so, Zeus is a confirmed villain.
Zeus was the god that dethroned Gaia, Chronos and the titans, and the Olympic Gods, dominated the Earth and the humans, and splicedit in four regions, connected with the humans: Tenkai (where the leaders lives, lead by Zeus), Sekai (the world of humans; maybe, the first reign; lead by Zeus), Kaikai (the watery world; lead by Poseidon) and Meikai (the world where the humans goes; only the purest, goes to the Elysium. Meikai and Elysium are lead by Hades). Each Olympic gold, lead a thing connected with the humans; Ares, forexample, lead the war.
But, the three Zeus's sons (Abel, Artemis and Athena) keep the earth. Artemis, control the Moon in the Earth, and Abel, control the Sun; so, they were the gods responsible to keep the day and the night in the Earth; Abel was substituted by Apollo after his rebellion. Zeus leaves the Earth with Athena, and Athena, without a divine body, was born with a human body (Zeus was her ally, and madeherself born every 200 years, and the gods every texted the actual Athena to see if she is Athena), so, she always dead in various ages, with humans feelings and pains.That's done Athena loves the humans, even with their sin, considering these sins, the normal way of being, always preaching for the pardon of all human sins. This caused the fury of Poseidon and Hades. Zeus was an Athena allied until the XX Century (he was at her side in the battle against Saga, because Saga wanted to dethrone the legitimate goddess of the Sekai [Athena] and attacks other gods, like him) when Athena refuses to allow Zeus allies to kill the humanity; Zeus doesn't know about Athena intentions to help the humans, and because this, was her ally. Possibly, in the future, Zeus and Olympic Gods (according Poseidon) will fight with Athena, to reconquer the Sekai and revenge the death of Hades and Abel and the defeat of Poseidon.