Pyramid

Pyramids are massive tetrahedral vessels that make up the armada known as the Black Fleet.

Overview
Pyramids appear to vary widely in size, but the ones seen currently in the system are nearly twice the size of a Fallen Ketch. They all share a simple tetrahedral shape, broken up by lines of yellow-orange lights. They are accompanied by fleets of smaller entities known as Pyramid Scales; about the size of a jumpship, these objects are hexahedrons with floating dagger-like extensions extending from their undersurface and are made of the same chiseled obsidian-like material as the larger Pyramids.

It is unclear to what degree the Pyramids can be considered vehicles or fully autonomous machines analogous to the Traveler. Based on Guardian's exploration of the Lunar, Europan and Sunken Pyramids, the Pyramids have interior spaces designed for roughly human-scale inhabitants; the Europan pyramid is also filled with numerous artifacts pointing to its habitation, including what appear to be workstations at which partially-completed statues of colored stone sit unfinished. These statues vaguely resemble humanoid or equine figures, but it is unclear what, if anything, they actually represent. Both pyramids also contain what appear to be urns of various shapes and sizes, either arrayed in open spaces or stored in racks set into walls. Thus far, only one "native" Pyramid inhabitant has been encountered: Rhulk, Disciple of the Witness, who commanded the Sunken Pyramid in Savathûn's Throne World. The Witness has also been shown aboard a Pyramid, presumably the commanding Pyramid of the entire fleet. It is unknown at this point whether all other Pyramids are home to a single Disciple, or whether some contain armies or are empty of life entirely.

Design and architecture
The architecture of the Pyramids tends to be minimalist and geometric, but with many intricate details and a variety of construction materials. The atmosphere inside is generally oppressive and foreboding, featuring chambers and hallways illuminated by harsh red and white lights, deep chasms or pits whose depths are obscured by mist, and huge bleakly-illuminated open spaces stretching for many kilometers into the distance. Most distinctive of all is a chamber atop a vast staircase that hosts a massive sculpture of what appeared to resemble a veiled humanoid figure. An identical chamber was also found within the Europan Pyramid, perhaps indicating that all Pyramids contain such a room. The significance of these statues remains unclear. Although the Lunar Pyramid had been left buried beneath the surface of Luna for many centuries, if not millennia, numerous sounds can be heard within its walls including harsh whispers, an ever-present hum of machinery, and distant howls.

Within the Ionian Pyramid, a unique chamber was discovered in the form of a cavernous shrine. At its center, a stone idol of a Pyramid stood before numerous effigies resembling several races, beyond which lay numerous pillars. These effigies included depictions of Hive, Fallen, Cabal, and Guardians of the Last City, all gazing up at the Pyramid. Shadows of the Pyramid stretch across the ground, reaching out towards the surrounding races, the largest of which extends out towards the Fallen.

The Sunken Pyramid within Savathûn's Throne World seems to display a degree of personalization based on the aesthetic desires of its resident, the Disciple Rhulk. Many walls are adorned with murals or seemingly abstract colored shapes, some of which are explicitly representational and others whose purpose or meaning, if any, is unknown. Rhulk also has placed a number of displays throughout his domain, including a pedestal supporting a rib bone from the Leviathan of Fundament, which he personally removed from the beast during their confrontation. It is unknown whether all Pyramids display this level of customization.

Capabilities and technology
As discovered by Asher Mir through his experimentation, Pyramids have a defensive mechanism where incoming projectiles appear to simply disappear on the point of impact, while still physically existing in some form. This defense also seems to suppress electromagnetic radiation to a degree, requiring a fully equipped relay system to remain detectable from the outside.

On Europa, several artifacts originating from the Pyramids have been encountered, including Stasis Locks, Cruxes of Darkness, Splinters of Darkness and the Ziggurat.