Anger is a great business, people will share it with you for free and if you're savvy enough, you can sell it back to them. The Rage Mages descended from Belligerus's early followers have found that modern world has just as much use for anger and magic as the ancient world.
From an episode of Justice League Unlimited:
The God of War creates a giant, unstoppable robot (golem, animated armor, etc.) as a weapon for one side in a civil war; his purpose is to prolong the war and create suffering and war among humanity.
Quote from Ares in that episode, which would go well with this idea: "That's all you mortals are good for! To fight and fight and fight until there is nothing left but charred land and blood and bones, and to end it all and then start again with the next generation!"