The Ghost of Darkness is an evil ghostly entity in the form of a skull that is Rita Repulsa's creation and a minor villain in Mighty Morphin' Power Rangers.
He lives somewhere out in space. Rita had approached him with a request from Lord Zedd. The Ghost of Darkness had heard of the wedding between Rita Repulsa and Lord Zedd. Rita was kneeling before Ghost of Darkness and bowed to him several times. Lord Zedd wanted to send the Rangers back in time.
The Ghost of Darkness had commented that they needed to get rid of the White Ranger first. The only thing to defeat White Ranger would be someone of equal abilities.
The Ghost of Darkness sent down the Wizard of Deception. The Wizard of Deception would create the evil Green Ranger by taking a lock of Tommy's hair. The Wizard of Deception sent back Aisha, Kimberly, Adam, Billy, and Rocky into the past, the colonial era.