"Close your eyes... I want to show you something."; "I will haunt you forever!"; "Pffffrrrrrrrrrrrr."; "I will make you scream."; "Take a ride with me."; "Weeeheeheeeheee!".
Runs away at deep red, often using haste then.
Creature added in the Christmas 2006 update. Often hunted for Death Rings and Demonic Essences, since it's one of weakest monsters that can provide such items. In Formorgar Mines, these creatures are often hit to red or lured away in order to hunt other creatures such as Destroyers or Plaguesmiths because Nightmares combo High (450-550) sometimes and can be a deadly surprise combined with other creatures.
Don't try to outrun them, Nightmares are pretty fast, resembling the speed of a Level 110. Having them close to you makes them use more melee than their strong attacks. Their Poisonball attack is very strong, and can easily lead to death if you are not paying attention. Try to kill them in such a way that they will trap themselves when they begin to run. They run away when they have less than 300 hp. If you are a mid-to-high level vocation (specially paladins and mages) and you are hunting them at the Cemetery Quarter don't try to block 2 Nightmare Scions while killing a Nightmare they can take you down even in one hit. If you're blocking a Nightmare and oneNightmare Scion, try to kill the scion first. But, if the Nightmare is in red hp try to kill him fast. It is a good idea to bring a Silver Amulet that can be bought from Alesar for 100gp since it will block 30hp on average and will not wear off fast because nightmares do not poison you with their attacks.
Knights: Killing Nightmares as a knight has 2 good strategies.
The first and easiest way to kill Nightmares is having 2 or more knights of Level 80 or more simply lure it, then trap it and hit it until it dies.
The second way can require a bit more experience, having one knight of Level 85 or more and a Druid of Level 50 or more to Sio you. Simply lure the Nightmare, try to trap it, and kill while a druid is healing you, keep in mind that the Nightmare can easily hit you for 700 damage in a nasty combo, so it is not a bad idea to bring some potions for the blocker or UHs for the mages to use on the knight. At about Level 95, knights can solo Nightmares with ease. Note: Knights, DO NOT HAVE CHASE OPPONENT ON! YOU CANNOT HEAL ALL THE TIME! If you have chase opponent on you are more likely to run into more creatures and get combo'd. Also Nightmares have extremely low defense, Exori attacks are very strong. Their melee is very weak (comparable to a Mutated Rat or a Dragon) and they don't have any wave so diagonal isn't necessary. Paladins: Level 80 recommended. Exura San at 700-800 hp don't let your hp go lower than 700. Royal Spears, Enchanted Spears or Assassin Stars are all that is needed besides 80 distance and 1 to 10 Strong Mana Potion per Nightmare and some Strong Health Potions for emergencies.
Mages: Mages of Level 70+ can solo Nightmares with only Elemental Strikes, rod or wand and Utamo Vita, levels 130+ can kill with just exura and using Terra Set, when it begins to run away in low health, you may try to use various runes or waves (any with non-death damage). Also mages can try to solo them with Ice Strike, using Light Healing without waste, having Level 140 or higher.