@Frostmourne is a terrifying, sapient runeblade of immense cosmic power, serving as the primary instrument of the @Lich King’s malice. The blade is forged by the demons of the @Burning Legion—specifically the Nathrezim (Dreadlords)—to contain and channel the vast necromantic energies of the imprisoned orc shaman, Ner'zhul.
When Kil'jaeden cast the Frozen Throne down into the icy wastes of Northrend, the Lich King purposely thrust Frostmourne out of his icy prison, causing it to land in the desolate, cavernous vaults of the Dragonblight. This act is a deliberate, baiting trap. The blade acts as a physical anchor for the Lich King’s telepathic will, designed to lure in a champion powerful enough to break the throne while systematically destroying their sanity from afar.
The primary victim of Frostmourne's curse is Prince @Arthas Menethil, the heir to the kingdom of Lordaeron. Desperate to save his plague-ravaged homeland from the @Scourge, @Arthas Menethil led an expedition to @Northrend to find a legendary weapon capable of defeating the dreadlord Mal'Ganis. Guided by the explorer Muradin Bronzebeard, @Arthas Menethil discovered the runeblade resting upon an altar of ice, guarded by elemental spirits who warn him that the weapon is cursed.
Ignoring the omens, @Arthas Menethil swore to gladly take any curse to save his people. The moment @Arthas Menethil gripped Frostmourne, the blade violently tears his mortal soul from his body, consuming it within the steel. No longer a @Paladin of the Light, @Arthas Menethil rose as the premier @Death Knight of the @Scourge. He returns to Lordaeron and immediately uses @Frostmourneto murder his father, King Terenas Menethil, plunging the @Humannation into absolute apocalypse.
@Frostmourne is an artifact of absolute necromantic perfection. Its primary capabilities include:
Soul Consumption: Every living being slain by the blade has its soul instantly ripped away and trapped within the dark matrix of the steel, feeding the sword's power and granting the warchief access to the victim's memories and skills.
Absolute Necromancy: The blade allows its wielder to instantly reanimate the dead as loyal Scourge thralls. It is used to defile the high elven Sunwell and resurrect the archmage Kel'Thuzad as an immortal Lich.
Cryokinetic Mastery: The blade radiates a supernatural, absolute cold, capable of freezing flesh on contact and shaping ice into deadly constructs.