Nightmare Mode is a difficulty setting, unlocked upon completing the campaign in War Mage Mode. It is the most difficult available.
- Decreased player health by 50%
- Decreased rift points by 50%
- Increased Mob health by 20%
- Increased Mob damage by 20%
- Orc Warriors have Shields
- Guardians receive 20% less damage.
- All breaks between waves (including at the start of the stage, before the first wave is unleashed) are only 3 seconds long. In OMD2 the player is given the first Go Break (before first wave starts).