King's Bounty: Legends offers different kinds of quests:

  • Main Quests - They advance the story and have a special 'crown' symbol before them in the quest log.
  • Side Quests - Not part of the main story, but often give nice rewards (Immortal units), can only be done once though.

Not really quests, but Wanted Battles are an important aspect of the game, to collect Immortal and Legendary units.