Vengeful Spirit
The Vengeful Spirit is the Gloriana-class battleship that served as the flagship of Horus Lupercal during the Great Crusade and the Horus Heresy. Currently, it is under the command of Abaddon and serves as his flagship when he's not riding in a Planet Killer or Blackstone Fortress.
One of the few Gloriana-class ships ever built, the vessel acquired a fearsome reputation during the Great Crusade, which only increased during the Heresy. By the time of the Siege of Terra, the ship was essentially a space-borne temple of the Chaos Gods. The final confrontation between Horus and the Emperor took place on the corrupted bridge of the ship.
Ezekyle Abaddon took command of the Vengeful Spirit during the retreat from Terra, and proceeded to fly it deep into the Eye of Terror. Somehow, he managed to get it through the huge, permanent, destructive storm of psychic fire that surrounds the "Radiant Worlds" and hide it on an old Eldar world while he went into an emo phase and wandered aimlessly around the Eye.
Upon learning that Fabius Bile had cloned his father, Abaddon finally stopped moping and, with a skeleton crew of Chaos Marines who would become the Black Legion, used the vessel to utterly destroy the Emperor's Children at the Battle of Harmony. Since then, he has used it as his personal flagship. While the Planet Killer briefly displaced the Vengeful Spirit as the Black Legion's flagship during the Gothic War, the destruction of the Planet Killer saw the Vengeful Spirit retake its place at the head of the Black Legion's fleets. The vessel was confirmed to be part of the Traitor Fleet that attacked Cadia during the 13th Black Crusade, and was the vessel Abaddon escaped to when Cadia was destroyed. Presumably, the Vengeful Spirit is now leading the Black Legion fleet on a rampage through the galaxy.
Appears in Gothic Armada 2.
For its Loyalist opposite number in the current timeline, see Macragge's Honour, the flagship of Lord Commander Roboute Guilliman.