Generally in video games, bosses are enemies that fight you at the end of a level or at a significant point in the story. Bosses usually differ from normal enemies by generally being more Powerful. Bosses usually have more health, deal more damage, etc. Many times, bosses have different stages which alter their attacks or change up their weaknesses forcing the player be vigilant for a sign of weakness. Generally a boss will know who the main character is or will be somewhat connected to the final boss of the game.