This tomb was the final resting place of Sith King Dathka Graush's mummified remains after his assassination in the year 6950 BBY. Graush's fifty-year reign of terror and cruelty produced a dizzying amount of corpses, which he then experimented on using Sith magic and alchemy to produce a zombie army. At some point in his life, Graush had replaced his heart with a dark side Force-sensitive crystal, which, after his death, was used to capture the spirits of his zombies. The crystal was laid to rest with Graush's remains and the zombies lay dormant until a being touched the Heart.
Sources
Korriban: Planet of Lost Souls on Wizards.com (backup link) (original site is defunct)- The Complete Star Wars Encyclopedia (see Heart of Graush and Korriban zombie)
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