In Greek mythology, Zeus is not killed at all. Zeus is king of the Greek gods and goddesses, a role he takes on after defeating his own father.
However Zeus is then confronted with one final adversary, Typhon, which he quickly defeats. Now clearly the supreme power in the cosmos, Zeus is elected king of gods.
After Kratos killed Zeus, the latter also took an astral form, and forced Kratos into his own psyche. Kratos escaped his psyche, however, and successfully battled Zeus' astral form with the power of Hope.
The two powerhouses face off in a heated battle between father and son. Kratos stabs Zeus with the Blade of Olympus, then Zeus uses the blade against Kratos. But Kratos finishes the deed by beating Zeus to a bloody pulp with his bare hands (not unlike how he defeated Hercules).
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Later, Kratos would become a god himself as the God of War, but after he was (apparently) stripped of his godly powers and killed by Zeus, there was no one else to take the title of God of War.
He feels regret over killing his own father most of all.
Even telling his own son afterwards. "we must be better than this. '" meaning he ever wants his son to be alike himself.
Athena is the number one person that Kratos did not mean to kill, and showed great regret upon doing so. When he met her in the Underworld, he seemed dearly sorry that he had impaled her. Also, she seemed to be the only god he would listen to, save Hephestaus.
God of War Ragnarok - Kratos Crying as He Becomes The God of Peace, The All Father - YouTube.
He's killed 19 Full blooded Gods.
Hercules then asked for help from the gods to end his life, and he received it. The Greek god Zeus sent lightning to consume Hercules' mortal body and took him to live with the gods on Mount Olympus. This was the apotheosis, the transformation of Hercules into a god.
The Greek poet Hesiod related two principal legends concerning Prometheus. The first is that Zeus, the chief god, who had been tricked by Prometheus into accepting the bones and fat of sacrifice instead of the meat, hid fire from mortals. Prometheus, however, stole it and returned it to Earth once again.
Nyx is older and more powerful than Zeus. Not much is known about Nyx. In the most famous myth featuring Nyx, Zeus is too afraid to enter Nyx's cave for fear of angering her.
While he wouldn't know it for most of his life, Kratos was a demigod as he is the son of Zeus, but he would later become a full-on god, the God of War to be precise, after killing Ares.
However, Kratos did not kill all the gods, and there are close to a dozen Olympians that managed to survive Kratos' path of destruction.
Throughout the Greek era of the series, Kratos is portrayed as a Spartan warrior, who becomes known as the "Ghost of Sparta" after accidentally killing his family due to the trickery of his former mentor Ares, the God of War. He later avenges the deaths of his family and becomes the new "God of War" after killing Ares.
There the Giants show Kratos to be the hero of Ragnarok -- more god of peace than god of war. Kratos is overwhelmed, even letting out a few tears and whimpers at the vision of him as a savior instead of an instrument of death and destruction, as he was in Greece.
It is documented that Greek gods grow stronger with age, and audiences have seen that with the sheer power and invulnerability of Old Kratos. As such, Old Kratos would win based on age.
In fear that Kratos, his son, would overthrow him, Zeus decided to betray and murder him. While Kratos was destroying Rhodes in an effort to be noticed by fellow gods, Zeus drained his godly power and gave life to a nearby statue, which was sent to kill Kratos.
Gaia betraying Kratos and allowing him to fall to his "death". Gripping to Mount Olympus for dear life, one of Gaia's hands partially snapped off due to Zeus' attack barely connected by enormous vines.
He is, however, quick to anger if someone crosses him or his family, which makes him an enemy of Kratos. As Kratos is traveling through his palace, Hades comments that there is bad blood between them, as Kratos had murdered his niece (Athena) and his brother (Poseidon).
He was a servant of Olympus, helping in defeating evil deities. As the series went on, however, Kratos became a much more villainous and sinister figure, due to his undying bloodlust and his vengeful, destructive behavior.
Despite Hercules animosity towards Kratos, it does appear they were close at some point, as they both address each other as brothers and he is the only Demigod/God Kratos was noticeably reluctant to fight.
He hates Ares for tricking him into killing his wife and daughter. He hates Zeus for attempting to kill him, but I always thought that was a little muddy motive. Zeus was justified for trying to stop Kratos as he was murdering everyone to begin with.
Moreover, Mimir had warned Kratos time and again about Odin's treachery. Thus, Kratos decided that it was in their best interests to not get into any kind of agreement with Odin, having had his fair share of ill experiences with other gods.