Key Ship

Mentioned only in the hidden Terminals found on the Ark and second Installation 04, Keyships were a class of Forerunner vessel capable of activating portals leading to the Ark. Though many more once existed, the majority, if not all, were destroyed by the Librarian to prevent the Flood from reaching the Ark.

The Forerunner Dreadnaught of Halo 2 and Halo 3 is most probably one of, if not the last surviving Forerunner Keyships in existence, utilised by the Covenant to gain access to the Ark. The vessel had evidently been found by the Covenant at some point, and was used by the Prophets to power their artificial homeworld, High Charity, until it was disconnected in 2552 in order to travel to Earth, carrying the Prophet of Truth to Earth. It connected with the portal generator once it had been uncovered from the ruins of the destroyed city of New Mombasa. The fate of this last vessel has not been verified, but it is likely that there remain no more Keyships in existence.