He got picked on as a kid, what with his mum having frolicked with a Godly Dolphin and him being born from her leg where a Godly fin had brushed it. (What kind of frolic is that? Ed).
So he grew up with a chip on his shoulder, vowed he was going to burn everything, and leapt into the sky to become the sun. His mum was just in time to throw clouds of lime into the sky to prevent him from burning everything to a crisp.