Father heaven hated anything abnormal and banished all his children except the titans to the underworld
Titan Crones, the ruler of the universe, had children and learned that one of his children was going to dethrone him so he swallowed them as they were born. His wife kept one hidden, his name was Zeus.
When Zeus grew older and found out what is father did he was furious and started a huge war against the titans and his father. Zeus won and banned the titans to the bottom of the earth forever.
Zeus had to fight many other monsters to remain in power. The world was free of monsters and it was ready for humankind. It was divided into two equal parts and humans lived on it.