Kewu-class battleship (EXverse)

The most powerful vessels ever built by the Covenant, the Kewu-pattern battleship is a class of extremely armed and armored warships built during the final year of the war against the human race. While having fewer weapon systems than supercarriers, it carries one of the most powerful lance ever fitted aboard a Covenant ship, which can sniping enemy ships from the longest distance ever seen, and the heaviest cruiser-grade shield ever fitted: for these reasons it was considered the most powerful Covenant ship at that point.
It was conceived by the Prophet of Regret himself for dual-purpose: on one hand, giving the ultimate strike to human forces, in order to shorten the war; on the other one, using it against Sangheili in case of emergency, since he didn't trust them a lot, much more when they tried to argue the absorption of human race into the Covenant many years later.
Designed soon after the first deployment of the around Harvest, however its building started much later due to resources shortages that afflicted the Covenant - which also led Truth to try to acquiring the Forerunner fleet stationed at Etran Harborage: so only two were constructed before the Great Schism at the end. One took part to the Fall of Reach, where it was destroyed after causing heavy casualties to the UNSC Navy, while the other one was lost since the start of the Blooding Years. However, only a handful of people knew about it, and while some of them tried to track down the powerful vessel, all efforts have been useless so far.