The Runner-class was a Covenant Naval vessel designed to transport the Hierarchs, known to be featured in the canceled Untitled Halo MMO  it was shaped similar to a Ghost. One such Runner-class ship was known as the Throne Warden.
It was completely manned by the Sangheili, and had a limited planet-to-planet distance, with no system-to-system FTL drives on board.
While developing the Halo games, Bungie, 343 Industries and Ensemble Studios have had to cut some content, such as vehicles, gameplay, and story elements, from the final products. Much of this content has been confirmed by videos and commentary in special edition DVDs, interviews with developers, and released concept art.