And as I said in the Sound section, you can hear Shakti order the units around as well. It works great, and really helps to make the game feel like more than a game. The game's basic commodities are mana and souls. Mana is an infinite resource, gathered at mana fountains which are usually scattered liberally around the map. But a mana fountain isn't as useful as a Manalith, as the Manalith directs all of the fount's mana directly to you.
Souls are probably more important than mana, and they're certainly scarcer.
There are a limited number of souls on each map, and every creature that you create takes up a certain number of souls. When a creature dies, their souls float above their bodies until they are collected or converted. Souls of your own side are blue, and can be collected by simply running over them. Casting the Convert spell on said soul will summon a sac doctor, who will cart the beastie's soul off to the Altar to sacrifice. And the Altar is the centre of Sacrifice .