This article contains major spoilers for Zack Snyder's Justice League. You have been warned.
Zeus, also known as Jupiter, was the king of the Old Gods, worshipped by the Amazons, ancient Greeks and Roman civilizations. He is the father of numerous children, which include: the fearsome God of War Ares, the Goddess of Hunt Artemis, as well as the heroic demigods Hercules and Wonder Woman.
When all the other gods were killed by Ares, Zeus fought and was able to defeat and grievously injured Ares, leaving him weakened, before he then used the last of his power to create an island called Themyscira where the Amazons could live hidden from humanity and from Ares, dying in the process.
Despite his death, his legacy lives on both through his daughter Diana, also known as Wonder Woman, and through the powers of the wizard Shazam and his champions, the Shazam family, whom are able to harness some of Zeus' power for their own use.
Ruling the Old Gods
As Zeus' son Ares started corrupting humanity with violence, Zeus with the help of the other Old Gods promptly created a new race in response - the Amazons, a species of women blessed with immortality and superhuman attributes, who were intended to protect humanity from Ares' influence by spreading both love and compassion.
Eons ago, before the modern day, Zeus led a coalition of humans, Amazons, Atlanteans, at least one Green Lantern, and his children, Ares and Artemis, against the armies of the New God Darkseid. Zeus killed several Apokoliptian Priests and Parademons, blasted back Darkseid himself with more subsequent divine lightning and split apart the nearly synchronized Unity. Following this, the forces of humans, Amazons, and Atlanteans divided the three Mother Boxes and kept them contained for millennia.
As Zeus was preparing to lead the Old Gods to the Amazons' defense to free them from enslavement and stop humanity from destroying one another, Ares, who still viewed humanity with envious disgust, violently rebelled, proceeding to kill the Old Gods one by one for disagreeing with his bloodthirsty and extremist ways. Instead of immediately participating in the war, Zeus decided to father a child with Hippolyta as a contingency weapon that could one day save humanity by defeating Ares once and for all, anticipating the possibility that he and the other Old Gods would die in the war. After Hippolyta was impregnated, Zeus fearlessly engaged his malevolent son in combat. Although Ares's powers had greatly enhanced, Zeus was able to defeat the God of War, banishing Ares from Olympus and grievously wounding him and leaving him badly weakened and much smaller, although he sustained severe wounds in the battle. Knowing that Ares would recover and return to create an endless war, which would destroy both mankind and the Amazon races, Zeus chose to sacrifice himself, using the last of his powers to create the protected island paradise Themyscira for the Amazons to live in safety, hidden from Ares and the dangers of the world and Diana would be safe until the time came for her to defeat Ares, an act of power that caused the King of the Gods to die due to his severe wounds made worse due to his overexertion of his powers.
Centuries after his death, his legacy lives on within Wonder Woman and the Rock of Eternity, the source of all magic. The wizard Shazam later bestowed his vast power upon one champion who he found worthy to carry on his mantle and become one of the overseers of the Rock of Eternity. Teth-Adam and the Shazam Family were granted Zeus' powers.
Zeus is known to have been incredibly powerful, yet equally benevolent and just, as well as divinely wise, since he would create humanity in the Old Gods' likeness (imbuing them with many virtues), and when Ares sought to corrupt them, he created the Amazons to protect humanity (imbuing them with the ability to spread love, compassion, and a mutual understanding among all human nations). Also, notably, when Ares first attempted to corrupt humankind, Zeus created the amazons to spread love and compassion in order to counter Ares' corrupting influence instead of actively interfering and killing him and simply drove back Ares during the War of the Gods, and banished the God of War, which showed that Zeus still loved, and did not want to kill his own son despite Ares' faults and everything he had done. This demonstrates Zeus' great love for his firstly created race, other beings, and his own family, as well as an extraordinary level of emotional intelligence and wisdom.
Zeus' fearlessness, nobility, and foresight are on display both when Zeus personally fights Darkseid, and later when despite Ares managing to slay every other Old God in the War of the Gods, Zeus faced his malevolent son in combat without hesitation and drove him back, in order to buy himself enough time to father Diana and create the protective paradise of Themyscira, so that when Ares returns, humanity will still have a godly savior capable of stopping the fearsome God of War. And indeed, Wonder Woman as a superhero seeks to uphold her late father's virtues and ideology.
If the myth mentioned by Lex Luthor (about Zeus cruelly punishing Prometheus) is true, then Zeus can be said to have a darker side, but given Wonder Woman's reaction of frustration and anger upon hearing the account, it is likely that the myth is actually inaccurate.
Powers and Abilities
Old God Physiology: As the King of the Old Gods, Zeus was a divine being of unparalleled power and might, and the most powerful of all the Old Gods, surpassing even his brothers Poseidon and Hades. He was considerably more powerful than the minor Old Gods, Amazons and super-powered Kryptonians. Lex Luthor used Zeus as one of the examples when describing the tremendous might of Superman. Zeus' extraordinary power was shown when he single-handedly defeated numerous Parademons and Apokoliptian Priests during Darkseid's First Invasion, and during the War of the Gods, despite Ares having been so enhanced by the violence that occurred to the point of massacring all the other Old Gods, even Poseidon and Hades, Zeus was still able to single-handedly face Ares when his powers were at their strongest on equal grounds and even eventually achieve victory and banish Ares from Olympus, with one single all powerful strike of thunder Zeus grievously wounding Ares to the point of permanently weakening the God of War and leaving him much weaker and smaller. Henceforth, Zeus's power was superior even to the resurrected Superman that bathed in sunlight, as he was able to stop the Mother Boxes with visibly greater ease than both Superman and Cyborg.
- Immortality: As the oldest Old God, Zeus is immortal, and has lived for millennia without visibly aging, with him far predating humanity and the Amazons, having created both of these races, as well as even being older than all the other Old Gods.
- Superhuman Strength: Like all Old Gods, Zeus possessed physical power far above any mortal, and as the King of the Old Gods, he holds the immense amount of strength, easily superior to super-powered Kryptonians, Amazons, New Gods and other Old Gods. He was able to overpower Ares in single combat, despite his son being empowered by the conflict of war, whereas all the other Gods were outmatched by Ares. His daughter, Diana imbued with lesser but still god-like strength, was able to fight a weakened Ares and ultimately defeat him.
- Nigh-Invulnerability: As the King of the Old Gods, Zeus possess the highest level of vast invulnerability an Old God can have, easily surpassing that of Superman, making him indestructible both to physical and supernatural means. While he could still be harmed by other beings of extreme power, given as how the violence enhanced Ares was able to severely wound him, his invulnerability, surpassing that of Poseidon, Hades and a violence enhanced Ares, was so great that even those beings have extreme difficulty harming or killing him, as Zeus emerged uninjured from his fight with Darkseid and was able to effectively resist the violence enhanced Ares's power enough to eventually defeat him and while Ares was incapacitated until he healed, Zeus retained enough power to create the shielded island of Themyscira and his death was mainly because he overexerted his powers while already being severely wounded. However, he still can be killed by a divine being of equal power like Ares in his prime form. 
- Life Creation and Power Bestowal: Zeus was known to have created both the human and Amazonian races (imbuing both with their mindsets and abilities, notably the ability of the Amazons to speak every human language), the latter race in order to bring peace to humanity. Zeus also fathered the extremely powerful Wonder Woman specifically as the Godkiller - a contingency weapon to be used to subdue Ares and the latter's warfare manipulation powers.
- Realm and Barrier Creation: Right as the War of the Gods drew to a close, despite being severely wounded and tired from his battle with Ares, Zeus was able to create the island of Themyscira and the extremely powerful magical wards that shielded the island, in order to guarantee the Amazons protection from the outside world and from Ares, a shielding that was so powerful that even Ares was never able to penetrate the island, although this cost Zeus his life.
- Electricity Manipulation:As the God of Thunder, Zeus has absolute control and was able to generate divine electricity to an unparalleled degree. Capable of summoning vast amounts of powerful celestial thunder into his hands and then precisely shaping them into blasts and bolts of lightning of unparalleled power, Zeus' electrokinetic powers were so potent and powerful, that with a single blast, he was capable of injuring and hurting Darkseid rendering him immobilized in the first Invasion of Earth, and he even grievously wounded Ares when his powers were dramatically enhanced by the violence of the War of the Gods with a single tremendously powerful lightning blast to the torso (forcing the wounded God of War to retreat off Olympus and leaving him much weaker and smaller even centuries after). Zeus even easily pried apart the nearly fused Unity with a single thunderbolt, a feat which visibly exhausted the combined efforts of both Superman and Cyborg. The Power of Zeus, which grants Shazam and Black Adam elektrokinesis is named after the late Old God.
- Flight: Zeus, as seen in Ares' War of the Gods illusion, could levitate himself off the ground and fly at extraordinary speeds, as both he and Ares remained in the air through their battle on Olympus and Zeus notably managed to outpace Ares's already extreme flight speed enhanced greatly by the violence that occurred in the War of the Gods.
- Genius-Level Intellect: As the oldest, wisest, and smartest of the Old Gods, Zeus had extraordinary levels of divine wisdom and intellect due to his tremendously long godly lifespan allowing him to obtain and refine the wisdom of the ages. His intelligence and wisdom far surpassed all other Old Gods, even Ares. Indeed, he had an unparalleled level of emotional intelligence and wisdom, demonstrated by his ability to imbue many virtues into both his human and Amazonian creations; he even knew of the darker traits of humanity, something that no other Old God apart from Ares knew. Zeus' emotional intuition and vast divine wisdom also granted him amazing foresight and exceptional strategic skill, with Zeus able to see through even the most intelligent and unpredictable of individuals' natures with pin-point accuracy, to correctly deduce how said person would react, and Zeus always seems to think many times ahead, and be able to create nearly flawless plans to counter said individual's intentions effectively, as evidenced before Zeus went to fight Ares, he fathered Diana in case he should die, so that humanity would have another divine being powerful enough to defeat Ares and protect them from other powerful threats, and while severely wounded after defeating Ares, Zeus was able to quickly deduce that Ares is not dead and would use all of his powers and focus to heal himself, even if improperly, as long as he can recover before Zeus, and destroy humanity before Zeus could stop him. Anticipating Ares would recover even if only partially and quicker than Zeus, Zeus decided to sacrifice himself so that the Amazons would survive Ares' return and Diana could safely grow up well until the time came for her to become the protector of humanity by creating the powerfully protected island of Themyscira to cut them off the danger that humans and Ares posed to them.
- Master Leader: Zeus, having been King of Mount Olympus and chief of the Old Gods for many millennia, was therefore an extraordinarily experienced, charismatic and accomplished leader, with his leadership inspiring complete loyalty in all the other Old Gods and he notably even managed to inspire sufficient loyalty from Ares that the God of War obeyed Zeus despite his distaste for the other Old Gods for centuries before he finally rebelled. He also was an amazingly skillful orator, as he was able to easily convince the Amazonian, Atlantean, human, and Green Lantern forces to form an alliance against Darkseid during the first Invasion of Earth and in addition to having the support of Artemis in the war, Zeus was even able to convince Ares to briefly set aside his distaste for humanity and the other Old Gods and join him. Zeus' charisma and competence made all the members of the alliance acknowledge him as the leader of the alliance and follow his orders without question. Zeus then led such a large alliance effectively enough without fail that he was successful in repelling Darkseid's invasion despite Darkseid's vast army and having conquered many other planets without fail, notably the only known commander with the sufficient level of leadership to do so.
- Master Combatant: As the King of the Old Gods and thus the greatest and most experienced fighter among his kind, Zeus had millennia worth of combat experience and intensive training and unparalleled mastery and knowledge of the combat arts, exceptionally formidable in the use of both armed and hand-to-hand combat. During the Invasion of Earth Zeus killed his fair share of the Apokoliptian forces. The most prominent display of his skill was during the War of the Gods, as when he finally engaged Ares when the God of War was at his strongest and deadliest in single combat, he was able to not only fight evenly with the violence-enhanced Ares, who was so much more deadly and powerful than ever that he had killed all the other Old Gods, but he even emerged victorious, grievously wounding and driving the God of War back off of Olympus, leaving him badly weakened and much smaller even centuries after, though Zeus sustained severe wounds in his own right.
- Omnilingualism: Zeus had the ability to fluently speak, read and understand all human languages, even currently dead ones.
- DCEU Zeus has several differences from his original Greek mythology counterpart - the original Zeus had not been the one to create humanity (Prometheus doing so instead), and had been far more narcissistic and cruel, in addition to being less wise, and loving.
- In some variants however, Zeus did create several variants of Mankind
- DCEU Zeus life and role with humanity are quite similar to the role of the biblical God for multiple reasons:
- Zeus and God both created humanity, bestowed them with many virtues, and greatly loved them.
- Zeus and God both defeated a former ally - and child - turned arch-nemesis (Ares and Lucifer), casting him out of the divine realm (Olympus and Heaven) for his rebellion and for envy of humanity.
- When the ancient Greek Stoics referred to Zeus, they referred to him as the timeless, unmoved Prime Mover beyond space and time (the general complex concept of God) that Aristotle and Plato spoke of - who the Romans called Jupiter (or sometimes Deus) - rather than a robed, grey-bearded man as commonly depicted.
- Jupiter, the fifth and largest planet of the Solar System, is named after Zeus' Roman name.
- Thursday (Iovis Dies in Latin), in most Romance languages, is named after Zeus' Roman name as well.
- In the DC Comics, the 'Z' from 'SHAZAM' is used to signify Zeus.
- Zeus must have been atleast 197,984 years old for him to create the early humans.
- Heinberg, Allan, Snyder, Zack, Fuchs, Jason (writers) & Jenkins, Patty (director) (June 22, 2017). Wonder Woman.
- Goyer, David S., Terrio, Chris (writers) & Snyder, Zack (director) (March 25, 2016). Batman v Superman: Dawn of Justice.
- Gayden, Henry, Lemke, Darren (writer) & Sandberg, David F. (director) (April 5, 2019). Shazam!.
- Everything we learned from our WONDER WOMAN edit bay visit with Patty Jenkins (2017) Gal Gadot