Zan, the Paladin.
Selecting this religion, you will be able to summon Amber Dragons to your side in battle.

Ambers have the incredible ability of bypassing any terrain hurdle, no mountain is too high, no frozen sea too wide for them to traverse.

Mobility is their greatest boon, adversely, it can also be considered their weakness as Lessers cannot always follow where the Dragon may fly.
It is generally advisable to have Lessers with your forms to help tilt battles in your favor (not to mention garner Fury from an otherwise Fury-less battle)
You may find yourself having to choose between Grunching/Terraforming a region, or sending your Dragon off alone without Lesser support.

The Amber is the Middle-weight form.
Relatively cheap for it's abilities & much stronger than the forms of rival Gods, Incinerak & Bork.
1 on 1 it will easily crush these lesser forms.
A good choice for some serious strength when pressed for Fury & Wonderful in the early to early-mid game.

You should consider the dragons to be the Assassins of the pack.
early to mid game, Zan is an efficient Killer when players are struggling to etch out their empires & strengthen their troops, later, stacked with other forms or sent on secret missions, they can remain a strong force throughout the game.