From Destinypedia, the Destiny wiki
The Sunken Pyramid is a Pyramid of the Black Fleet formerly commanded by Rhulk, Disciple of the Witness. It was moved to Savathûn's Throne World by Rhulk at the request of the Witness, so that Rhulk could keep watch over the Witch Queen and provide assistance in the form of an inexhaustible supply of Worm larvae. Upon Savathûn's rebirth in the Light, the Pyramid was neutralized and sank into the swamp below, with a Light curse subsequently placed upon it to trap Rhulk inside.
Overview and layout
Unlike its brethren, the Sunken Pyramid appears more open and less cramped but still possesses a similar chiseled rock-like texture seen on the surface and its inner sanctums. From the outside the ship appears cracked thanks to the efforts of Savathûn, the Witch Queen and her acquisition of the Light which is most notable for such a strong feat.
On the inside of the Pyramid however, it is much more open unlike its Lunar counterpart but similar to its Europan counterpart, possessing strange statues carved out of the same material as the ship along with massive structures in semblance of a city. Some of the statues appear like strange humanoid creatures and even horses.
The Pyramid also acts as a sort of library, cataloguing Rhulk's entire backstory through the use of murals. Some of these murals appear as depictions of Hive, the Witness, the Guardians and even the Traveler. Some of the more gruesome parts of this collection would be a rib of the Fundament Leviathan placed in one of its open rooms. Another gruesome addition would be the calcified and dissected Worm larvae seen throughout the ship, frozen in calcified constructs, dissected and separated in various segments. Some of these worms can also be seen planted onto the heads of calcified Scorn. All of this makes the Pyramid's interior disturbingly resemble a twisted sort of art gallery or natural history museum.
List of appearances