Indra
From the moment he was born, all the other gods knew their time was up. His parents were the sky god Dyaus Pita and the earth goddess Prthivi; he was born fully grown and fully armed from his mother's side.
First thing on his agenda, kill his own father. He then got his mate to make him a thunderbolt so he could go and kick the arse of some other dude who used to be the hardest god in godland.
He was known as a great drinker of Soma; sometimes he did this to draw strength, and when he did he grew to gigantic proportions to battle his enemies, but more often than not he drank to get drunk.
Hard but fair, he was. During times of drought he would give the people rain but if they failed to pay the appropriate tribute, he'd give them another drought.
That's Indra, the hardest and coolest god in godland.