The true origins and motives of the being known as Quintessa are unknown. She professed to be the creator and goddess of Cybertron, but in the distant past, her twelve guardian knights came to understand that she was not as benevolent as she appeared, and so stole her powerful staff and hid it on Earth.
In the present day, seeking to repair the shattered Cybertron—ravaged by the Autobot/Decepticon war—Quintessa took control of the deserted planet and began moving it across space, intending to replenish it by draining the lifeforce of Earth—or as she knew it, Cybertron's ancient enemy Unicron. To accomplish this, she required her staff, and under undivulged circumstances, made contact with the Decepticon leader Megatron, charging him with locating it for her.
As Cybertron entered Earth's solar system, Optimus Prime—who had previously left Earth in search of his creators—came across it and set down on its surface. As Optimus entered Quintessa's base, Quintessa intimated that she was the creator he had been searching for, which prompted Optimus to attack her, but she easily restrained him. Striking Optimus across the cheek, she left a red "scar" that spread over his face, placing him under her control. Redubbing him "Nemesis Prime", Quintessa dispatched him to Earth as another agent to search for her staff.
The brainwashed Optimus would ultimately fail in his mission as his old friends helped him break Quintessa's control, but not before the staff had been located. Megatron, however, snatched victory from the jaw's of Optimus's defeat, stealing the staff and delivering it to Quintessa as Cybertron arrived in Earth's atmosphere. Quintessa triggered the energy transfer from Earth to Cybertron, and charged Megatron with defending her as she used her own body as a conduit between staff and planets. A combined assault from the Autobots, humans, and Knights vanquished all her forces, but her own power remained more than enough to stop Optimus when he tried to take her on directly. Unfortunately for Quintessa, Optimus was only a distraction; his frontal assault left her open to an attack from the rear by Bumblebee, who blasted and seemingly vaporized her.
The Autobots and their allies subsequently stopped Quintessa's plan by recovering the staff and retaking control of Cybertron. Quintessa, however, was not yet defeated. Disguising herself as a human, she approached one of the scientific expeditions studying one of Unicron's horns in a desert. Cautioning them against touching Unicron, she offered them a way to kill him...
- Quintessa will become Brian and the Eeveelution Family's enemy in Brian and the Eeveelution Family's Adventures of Transformers: The Last Knight.
- Quintessa will become the Ed's, Thomas, and Twilight's new enemy in Ed, Edd, n Eddy's Ed-ventures of Transformers: The Last Knight.
- Quintessa returns in Wrath of the Country.