Zeus

Zeus was the Greek God of the Sky and King of the Gods. He was once a mortal, but was imbued with divine magical power by the Elders to stop the ruthless Titans. Zeus assisted in entombing Demitrius, Meta and Cronus along with the other Greek Gods and Goddesses. They then declared themselves as gods and forced the world to worship them, becoming the Greek Gods of mythology.

Throughout Charmed
Zeus was mentioned in a conversation between Piper and dark future Chris Halliwell.

Throughout Destined
It was said by Olympias to her son Alexander the Great, that Zeus was his alleged father.

Mythology
His father Cronus devoured his older siblings to keep them from dethroning him, but Zeus' mother brought him to the mountains where he was raised by his grandmother, Gaea. Once he became old enough, he returned to the Olympians and used a potion to make his father throw out his older siblings and promptly killed him. Afterward, he took over the throne and ruled the Olympians with pride.

This was directly mentioned by Paige Matthews in Charmed. While reading aloud from a book, she said that Cronus had once eaten his children to stop them from dethroning him. However, it only referred to once and full detail was never delved into.

Notes and Trivia

 * Olympias told her son, Alexander, that his father is Zeus;
 * He is responsible for the entombment of the Titans;
 * It could technically be said that Paige Matthews transformed into Zeus when she and her sisters had to defeat the Titans. This is because Paige became the Goddess of War. Though this isn't actually true, but only a technological inference;