Hack-and-slash role-playing games such as the original Dungeon Siege and Diablo take on whole new lives when you play them online. It's one thing to battle against dozens of monsters alone, but when you team up with other human beings, these battles can turn into fast-paced, frenetic battle royals as each member of the team struggles to keep up his or her end. The upcoming Dungeon Siege II, due out this summer, promises to expand upon the multiplayer formula even further by letting players control a party of characters within their own parties. Confused? Let designer Daniel Achterman explain.