From Destinypedia, the Destiny wiki
The Titan Pyramid is the name used to a massive alien vessel holding position above the New Pacific Arcology on Titan. Like its counterparts, this vessel is a part of the aforementioned fleet that attacked the Sol System during the Collapse, and which is affiliated (or synonymous) with the Darkness.
Overview and Layout
Like its brethren, the outside of the Pyramid's hull is covered in segmented panels that vary in pattern, with some having vertical lines and other with patterns resembling circuitry. Much like the Traveler, the surfaces of the Pyramid seem to be composed of some form of rock-like material, occasionally having an uneven or chiseled appearance, giving the ship an almost handcrafted quality. In contrast to its Moon counterpart, the Titan Pyramid is rougher in appearance, suggesting more wear and tear to its hull.
It is unknown if there is a habitable interior within.
Of the four Pyramids introduced in Season of Arrivals, it is the most difficult to see from an accessible location.
Season of Arrivals
Weeks following the Io Pyramid's arrival, the Titan Pyramid arrived with 2 others on its aforementioned planet. Following its arrival, it hovered ominously outside of the New Pacific Arcology and began terraforming the moon.