Depends on whether or not you are doing the "Good Orc in a Bad World" or a "Bad Orc in a Good World".

I've alwayd liked it when books and games humanize the classic villans, especially when villans are portrayed as simply doing what they need to and not some insidious plot of 'evil'.

I would use Nature, Death and Blood and leave out fire.

You might also want to mash together a few of your magical commanders. And only have a few different magic commanders, I would assume the Shamans and Witch Doctors wouldn't let magic be too prevelant in order to maintain control.