The Hand of Evil takes the place of your mouse cursor, and it is how you interact with the world. You can pick up your creatures no matter where they are, and any gold within your territory. Creatures in your hand are safe from attack. You can drop off your creatures within your territory, and gold within your Treasure Room (or give it to an unhappy creature). You can also pick up Chickens to feed creatures and save them a trip to the Hatchery, but don't let them take advantage.