To gain exp and gold you must kill your opponent. The winner can win up to 5 percent of the exp and gold from the loser. Killing a monster over and over again will results in lower gains.

It is even possible to erase the kind of monster from the world. Monsters will be kept alive until all his exp is gone. When you have buried your monsters you take his old armors and weapon to sell it, and that is your reward for digging a hole.