- "The dead king Dathka Graush replaced his own heart with this fist-sized ruby, which contained the souls of his foes."
- ―Sorzus Syn
Through the use of Sith magic and alchemy, the Sith King Dathka Graush replaced his own heart with a Force-sensitive crystal later called the Heart of Graush. The Heart of Graush was made of the same material as the crystals within Sith crypts that housed the spirits of vanquished Jedi Masters. Within the heart were the dark side spirits of thousands of long-dead Sith. Graush used the Heart to make himself almost invincible.
Following the arrival of the Dark Jedi Exiles on Korriban in 6900 BBY, the Jen'jidai Sorzus Syn took an interest in studying a multiplicity of preserved Sith artifacts, recording her notes on the subject in her chronicle. She described the Heart of Graush as one of the most powerful amulets she had encountered during this time, leading her to include a sketch of the crystal and an accompanying discussion of its design and purpose in her chronicle.
Thousands of years after the Graush's death, the captain of the pirate vessel Jynni's Virtue, Naz Felyood, discovered the Heart buried in a tomb in the Valley of Golg. This led to the Captain being possessed by Graush. In the end, Felyood's comrades destroyed Jynni's Virtue, and Felyood lost the Heart in the process. He wandered Korriban for a long time afterward, ageless, constantly searching for the Heart.