Every one of the Greek gods have Haephaestus as one of their last demi-gods. You 
should always choose him as he is the very best demi-god in the game. He has Titans
as his main creature, which are the most powerful, and his power- the vault of plenty
gives a slow trickle of resources in you stash. It doesn't seem like much, but before
you know it, you will have 16000 of each resource.