Acamar

Acamar was an elder evil from the Far Realm who had taken possession of one of the stars of Realmspace. Unlike normal stars, Acamar didn't have a fixed place in the sky but instead danced and wavered across Realmspace.

Description
Acamar was a dead star of utterly black inky nothingness that ate other celestial bodies that drew too close to it.

History
Acamar and the other Far Realm–infested stars of Realmspace were somehow related to the Eldest.

Acamar's hunger was endless, and when its influence on Toril was as its peak, it sent its agents, the Maws of Acamar, to devour everything they encountered in their path to sate the hunger of the dead star.

Acamar was one of the stars the warlock Japheth Donard sought out in 1396 DR, after having lost his pact with the archfey Neifion.