It was always suspected that the Ancients fled from your Rakata of long ago. But they were not driven away quietly, and then did not arrive defenseless.
—Prescyla Osiris
The Atercor, colloquially called the Dark Heart, was an ancient Kathol Superweapon that was capable of destroying planets, stars, or potentially even star systems by inducing quantum singularities via the directing of protomatter clusters. The Atercor was used on at least two occasions during the Oblivion Crusades, was a vital component in the creation of the Hellmouth, and was eventually summoned from Otherspace for usage in the Extant War.