Kronus didn't actually castrate his dad alone. Four of his Titan brothers helped by hiding at the four corners of the world, and waiting for their dad, the Sky, to come in and make out with their mom. When he came, they held him down by the four corners and Kronus castrates him with his sickle. With Uranus deposed, the Titan brothers then release their giant-brothers from the belly of their mom, Gaia (who get sent right back to the hell-pit they came from not too long after.)
(Hyperion, one of the brothers, is the god of the dawn, so he is considered to be at the East corner. He gets together later with his Titan-goddess sister, Theia, and fathers the Sun: Helios. The sun represents Enneagram Type 2, according to Helen Palmer, btw.)
So Kronus, the god of Time, becomes king, and his wife, Rhea takes up the role as Time's first lady- the goddess of fertility and motherhood. (Being married to Time meant she would come to represent the flow of time from generation to generation).
But at some point in his taking over the throne, Kronus' parents- Uranus and Gaia- propesy that one of Kronus' own kids is going to overthrow the his new government. Kronus is understandably nervous because that's exactly what he did to his own dad, so he swallows all of his children as they're born, just to make sure they don't try anything. But his wife, Rhea, doesn't like this, and so when she gets pregnant with Zeus, she goes to her in-laws, Uranus and Gaia, for advice on how to save this one child. They advise her to hide away when it's time to give birth, and set up a situation where he lives in a cave in Krete, nursed by a goddess and protected by some gods. Then when she's supposed to hand over her baby to Kronus, it's actually a stone wrapped in swaddling clothes. Very clever, mom and dad.
It works, and it's a good thing that out of all the swallowed children, she saves Zeus, because he grows up and becomes the king of the gods, the ruler of the sky, and the highest ruler of human kind. Zeus is a big deal. (In astrology, he rules Jupiter, the planet that represents luck and power.) So you can imagine, when Zeus grows up, and he's got some avenging of his own to do, and he's going to be really good at it.
He gets his dad to vomit up all of his siblings and forms an army with them- they call themselves the Olympians- and they decide to go to war against their dad and his old boys' club, the Titans. So basically there's an epic war between the younger Olympians and the older Titans for ten years. This is called the Battle of the Titans.
To be continued...