Bane's Heart was a distinctive carmine lightsaber crystal. Darth Bane presented it to Darth Zannah, his Sith Master, after the events of the Seventh Battle of Ruusan. She incorporated it into her double-bladed lightsaber, naming the weapon in honor of the crystal.
The lightsaber, along with the crystal, eventually fell into the hands of a Dark Jedi. This individual was subsequently murdered by General Grievous, the Supreme Commander of the Droid Armies serving the Confederacy of Independent Systems, either on Dica or Necropolis. Grievous stored the weapon on his personal starfighter. Later, Imperial forces recovered the starfighter and utilized the weapon as part of the N-K Project. N-K Necrosis wielded the Bane's Heart lightsaber during the Galactic Civil War until a group of spacers killed him and stole the crystal from his lifeless body.
When calibrated for use in a lightsaber, the crystal caused the weapon to generate an electrical discharge. Furthermore, it made the lightsaber difficult for anyone other than its rightful owner to wield.
Bane's Heart held the distinction of being the second unique-colored lightsaber crystal obtainable by players in Star Wars Galaxies: An Empire Divided, with Sunrider's Destiny preceding it. Its introduction occurred within the 2005 expansion pack titled Rage of the Wookiees. When equipped in a player's lightsaber, the weapon produced a purple-red coloration, which is a contrast to its described "carmine" hue.