Scarlet Keep

The Scarlet Keep is a massive Hive fortress established on the Moon. Its construction was overseen by Hashladûn, Daughter of Crota, who designed it to harness the energy of the Pyramid buried in the chasm beneath.

Overview
The Scarlet Keep's central tower, the Tower of Woe, acts as an amplifier for Hive magic, which also shields them from the Pyramid's influences.

The Keep appears to be gradually overtaking other nearby Hive structures, as patches of red, spined architecture can be seen within the Hellmouth, The World's Grave, the Temple of Crota and even the Shrine of Oryx.

History
The Scarlet Keep was created at an unknown time following the Red War. It was built by the remaining Hive Broods on the moon who consolidated into the Hidden Swarm. Hashladûn, Daughter of Crota lead the Swarm in designing it to amplify their magic and allowing the Cryptoglyph's spells to shield them from the Pyramid's influences. When the Vanguard assaulted the Keep, they secured the entrance and opening it up for Guardian exploration. Later, Hashladun would lure the Guardians up the Keep, culminating in a final battle at the top of the Tower of Woe. Following the deaths of Hashladun and Besurith, the area around the Keep would be used as a ritual ground for the Hive to sacrifice nightmares to harvest their Phantasmal Essence.

Years later, while the Scarlet Keep would fall under the purview of Xivu Arath's forces, it would become a contested zone between forces loyal to the War God and those of the Lucent Brood, Lightbearing Hive of Savathûn, the Witch Queen. The Lucent Brood planned on using the Scarlet Keep as the center point for a ritual, using Light stolen from Guardians, to launch an invasion of Earth. Unfortunately for the Hive, the Guardians, working alongside the Cabal of Empress Caiatl, would be able to disrupt the ritual, thwarting the invasion.

Dark Future Timeline
In the Exo Stranger’s Timeline, the Scarlet Keep became a base of operations for Eris Morn, when the remaining Earth Guardians, Mara Sov, Cabal and Fallen began their attack, they were met by Hive and Dark Guardians. Zavala became supercharged by the captured Travelers Light and used his power to utterly destroy the Keep.

List of appearances

 * Destiny 2: Shadowkeep