Nightmare (Destiny)

Nightmares are shape-shifting entities created by the Darkness for psychological warfare. Their physical form is manifested from the trauma of their victims.

Overview
Nightmares are formless entities conjured by the Darkness based on the memories of those who encounter them. Such memories evidently need to be painful, traumatic memories, as Nightmares tend to assume the form of individuals their victims either cared for and lost, or suffered because of them. Nightmares also seem to mimic the capabilities of whoever or whatever they are impersonating.

History
Nightmares were first discovered on Earth's moon by Eris Morn, a Human Guardian scarred and altered by her history with the Hive. Delving deep within the moon to investigate Hive activity, Eris discovered a massive black pyramid, a remnant of the Darkness fleet responsible for the collapse of Human civilisation centuries earlier. Almost immediately upon this discovery, Eris became haunted by apparitions of her fallen friends, all of whom were killed by the Hive prince Crota many years earlier on that very moon.

Concerned about the resurgent Hive activity, the Guardians launched a full-scale assault on the Scarlet Keep of the Hidden Swarm. After delving into the keep's interior, a lone Guardian was ambushed by a group of Hive Thralls which seemingly appeared from thin air. After dispatching the Thralls, the Guardian's Ghost registered confusing scans indicating they were not Hive at all. Shortly afterwards, the Guardian discovered the Pyramid, but was ambushed by a Nightmare assuming the form of Crota. After a brief fight, the Guardian became overwhelmed as two more Nightmares appeared. One assumed the form of Ghaul, Dominus of the Cabal. The other becoming Fikrul, Archon of the Scorn. The Guardian was rescued at the last moment by Eris, who intended to enter the Pyramid and learn more about the Darkness.

In order to infiltrate the Pyramid, the Guardian needed to harvest enough phantasmal essence from the Nightmares now haunting Earth's moon. Such Nightmares assumed the forms of the Guardians' most powerful and hated enemies, including Omnigul the consort of Crota, Skolas the Kell of the Eliksni House of Wolves, Taniks the Eliksni mercenary and Phogoth the Hive Ogre. With enough essence harvested, Eris was able to assemble a suit of Dreambane armour for the Guardian. With this armour, the Guardian entered the Pyramid and fought the Nightmares of Ghaul, Fikrul and Crota once more, all whilst the Witness taunted them on the weakness of the Light. Since this incident, Nightmares have continued to haunt Earth's moon and reinforce the Hive presence there. The Hive have also ritualistically harvested the essence of the Nightmares for their own purposes, imbuing it into a Hive Knight called Zulmak to create a Nightmare-enhanced champion. Eris was also able to banish the Nightmares of her fireteam thanks to the recovery of their personal effects, reminding her of more positive memories of them and thus nullifying the Nightmares' influences.

Years later, Calus, the deposed Emperor of the Cabal, communed with the Lunar Pyramid and created a link between it and his ship, the Leviathan, in order to secure his place as a disciple of the Witness. This resulted in Nightmares manifesting on Calus' ship, reinforcing his Loyalists and Scorn. Before the Guardians could thwart Calus' plans, they needed Eris' help to neutralise the Nightmares he was weaponizing. Aboard the Leviathan, Crow was haunted by the Nightmares of Uldren Sov and Fikrul, manifested from his guilt over the crimes he committed in his past life. Commander Zavala was confronted by Nightmares in the form of his late wife Safiyah and his son's killer, Kethiks, both of which were drawn from his self-blame for his past shortcomings. Caiatl, daughter of Calus and Empress of the Cabal, joined the Guardians in the hunt for her deranged father, only to be confronted by the Nightmare of Dominus Ghaul, accusing her of crippling the Cabal after his downfall. With the help of Eris Morn, these individuals were able to come to terms with their traumas and the Nightmares became Memories, their forms becoming more accurate to how they are remembered.