Dragons of Nightmare The Dragons of Nightmare ( a . k . a . the Emerald Dragons and the Four Dragons ) are Lethon , Emeriss , Ysondre and Taerar . These dragons were world spawns located in Duskwood ( Twilight Grove ) , the Hinterlands ( Seradane ) , Feralas ( Dream Bough ) , and Ashenvale ( Bough Shadow ) . Background . In recent times , Ysera ' s most trusted lieutenants have been warped by a dark new power within the Emerald Dream . Now these wayward sentinels have passed through the Great Tree s into Azeroth , intending to spread madness and terror throughout the mortal kingdoms . Lethon . Lethon ' s exposure to the aberration within the Emerald Dream not only darkened the hue of the mighty dragon ' s scales , but also empowered him with the ability to extract malevolent shades from his enemies . Once joined with their master , the shades imbue the dragon with healing energies . It should come as no surprise , then , that Lethon is considered to be among the most formidable of Ysera ' s wayward lieutenants . Emeriss . The mysterious dark power within the Emerald Dream has transformed the once - majestic Emeriss into a rotting , diseased monstrosity . Reports from the few who have survived encounters with the dragon have told horrifying tales of putrid mushrooms erupting from the corpses of their dead companions . Emeriss is truly the most gruesome and appalling of Ysera ' s estranged green dragons . Ysondre . Once one of Ysera ' s most trusted lieutenants , Ysondre has now gone rogue , sowing terror and chaos across the land of Azeroth . Her formerly beneficial healing powers have given way to dark magics , enabling her to cast smoldering lightning and summon the crazed spirits of druids trapped within the Emerald Dream to aid her . Twisted and insane , Ysondre is bent on unleashing vengeance upon the mortal world as if Azeroth were the force behind the Emerald Dream ' s corruption . Taerar . Taerar was perhaps the most affected of Ysera ' s rogue lieutenants . His interaction with the dark force within the Emerald Dream shattered Taerar ' s sanity as well as his corporeal form . The dragon now exists as a specter with the ability to split into multiple entities , each of which possesses destructive magical powers . Taerar is a cunning and relentless foe who is intent on turning the madness of his existence into reality for the inhabitants of Azeroth . Strategy . They were raid - level difficulty , though some dragons were more challenging than others . All four dragons share the Sleep ( summoning " Dream Fog " ) , Noxious Breath , Tail Sweep , Mark of Nature and Aura of Nature abilities . Each dragon also has a few unique abilities . One of these is considered the dragon ' s ace move , and will be performed when the dragon loses 25 ± 5 % of its max life . In other words , the ace move will only be performed three times ; when the dragon is at 25 % , 50 % , and 75 % life . When it is performed , the dragon will also yell something . See the individual dragons ' page for abilities and specific strategies . In Cataclysm . All the dragons were removed from the game except Ysondre . In Legion . Most of this group of dragons have been further corrupted , and can be defeated in the encounter Dragons of Nightmare by players daring enough to venture into the Emerald Nightmare raid , accessible atop the tainted world tree Shala ' drassil in Val ' sharah .