The Dead Scar is a path of Blight that runs through the Kingdom of Quel'Thalas. During the Third War, the armies of the Undead Scourge — led by the death knight Arthas Menethil, Crown Prince of Lordaeron — marched up this path from Lordaeron all the way to the Sunwell Plateau, killing everyone and destroying everything in its path. The Dead Scar practically splits Quel'Thalas in half, all the way through Silvermoon itself.
Today, the Dead Scar remains in the rebuilt Quel'Thalas, as a reminder to all who live there of the horrors committed by the Scourge — and as an incentive to seek their destiny beyond the Dark Portal...
After tracking down the source of the Scourge, Prince Arthas joined with his old friend Muradin Bronzebeard in Northrend. Muradin told Arthas of a powerful runeblade called Frostmourne, which would give its wielder absolute power. Battling legions of the undead and defeating the guardian of the blade, Arthas and Muradin managed to locate Frostmourne, but Muradin realized the blade was cursed. Trying to dissuade Arthas from his course, Muradin was wounded by the incredible power released when Arthas took the blade from its pedestal. The blade did indeed give Arthas untold power, but it also had an unfortunate drawback: it stole the Prince's soul, and twisted his mind. He was now a slave to the Lich King, the first and greatest of his death knights.
After returning to Lordaeron and murdering his father, King Terenas, Arthas was instructed by the dreadlord Tichondrius to bring the corpse of the necromancer Kel'Thuzad (whom Arthas had killed not long before) to the Sunwell, the source of the high elves' magic. After obtaining a means to transport Kel'Thuzad's remains — the urn of King Terenas, guarded by Uther the Lightbringer and the surviving paladins — Arthas and the Scourge began their march across the Plaguelands of Lordaeron to the gates of Quel'Thalas. Smashing through the Elfgates that defended Silvermoon from invaders, Arthas' forces destroyed all in their path, killing everyone they saw, and blighting the very land they trod upon. The path they took across Quel'Thalas remains burned into the soil today, from the entrance to Quel'Thalas (north of what is now the Eastern Plaguelands) all the way through Silvermoon, splitting the elven capital in half, before ending at the doorstep of the Sunwell itself. By the end of the campaign, Kel'Thuzad had been resurrected, and the Sunwell defiled — thus cutting the elves off from their source of magic.
As the blood elves begin to rebuild their homeland, the Dead Scar remains a blight on the otherwise intact lands of Quel'Thalas. It begins at Deatholme, the Scourge headquarters in Quel'Thalas, and runs through the Ghostlands and across the Elrendar River into Eversong Woods. The path then continues across Eversong Woods and through the shattered main gates of Silvermoon. The path abruptly stops on the coast of the North Sea, but picks up once more on the southern tip of the Isle of Quel'Danas, the location of the Sunwell. There, about midway through the island, the path ends, overlooked by eredar warlocks, wrathguards, and pit lords in the service of Kil'jaeden, battling the remnants of Arthas' forces all up the path. At the northern end is the pit lord Brutallus, who commands the battle against the Scourge remnants, all the while verbally sparring with the blue dragon Madrigosa.
At the East Sanctum of Eversong Woods, located along the edge of the Dead Scar, Apprentice Mirveda conducts tests of the soil and has come to the conclusion that the damage done to the land of the Dead Scar is irreversible — another reason to leave Quel'Thalas and seek the destiny promised in Outland.
The undead presence along the Dead Scar is still considerable, even near Silvermoon; though they are fairly weak, their numbers are enough to keep the Silvermoon Ranger Corps busy, fending off the undead marauders. As one travels down the Dead Scar into the Ghostlands, the undead minions become stronger. The strongest undead legion in Quel'Thalas is behind the walls of Deatholme, the Dead Scar's southern terminus — where the traitor Dar'Khan Drathir and his lieutenants command the Scourge efforts in Quel'Thalas.
Also, in the Isle of Quel'Danas at the Sun's Reach Sanctum, Battlemage Arynna gives a quest called to kill two Pit Overlords, three Eredar Sorcerers, and 12 Wrath Enforcers. The quest is done by first talking to Ayren Cloudbreaker in order to ride a Dragonhawk, then are dropped from the air when arriving at the Dead Scar.
- The Dead Scar appears in the introduction cinematic of World of Warcraft: The Burning Crusade in what is referred to on the Burning Crusade Behind-the-Scenes DVD as the "Raptor Shot".
- In World of Warcraft the Dead Scar actually ends at an intact doorway at the back of Silvermoon City, some 80-100 yards before the North Sea. Why exactly it wasn't done all the way is unknown. Possibly because accessing that part of the map, without a flying mount, is very difficult. You have to swim from the coast of Sunstrider Isle and be sure to stay close to the coast so you do not get Fatigue and die.
- The remains of Thalorien Dawnseeker, the high elf who wielded the legendary sword Quel'Delar, can be found at the southern part of the Dead Scar in the Isle of Quel'Danas.