The objective in the game is to kill all monsters. However you can hardly do it alone. In order to win you need to cooperate with the NPCs (Non-Player-Characters). They have various professions and belong to various races.
They usually do their work and store the outcome in the houses, but they will willingly follow you if you ask them to. A party of several NPCs is strong enough to kill an orc, a bear, sometimes even a dragon.