The Mournival was the advisory war council of four Space Marine Captains of the Luna Wolves Space Marine Legion that served their Primarch and Warmaster Horus as advisers and close companions throughout the Great Crusade until the start of the Horus Heresy. However, the Mournival was only a cultural tradition of the Luna Wolves and carried no official weight or duty within the Legion's command structure and was not used by any of the other Legiones Astartes. In the last days of the Great Crusade, the Mournival was composed of four of the most famed officers of the Luna Wolves: First Captain Ezekyle Abaddon of the 1st Company, Captain Horus "Little Horus" Aximand, Captain Tarik Torgaddon of the 2nd Company and Captain Garviel Loken of the 10th Company. Before being chosen to join the Mournival, Loken's place had been filled by Captain Hastur Sejanus of the 4th Company, a particularly beloved friend of Horus who had been murdered during the negotiations to gain Imperial Compliance of the world of Sixty-Three-Nineteen. The First Chaplain Erebus of the Word Bearers Legion later took on the appearance of Sejanus through the use of sorcery during Horus' healing in the Temple of the Serpent Lodge of Davin to deceive him and lead him towards corruption by the Chaos Gods.
Those captains of the Luna Wolves (and the Sons of Horus after the Legion's name change) who were chosen to serve in the Mournival were generally considered the best officers of the Legion by their fellow Battle-Brothers. In general, each of the four members of the Mournival were chosen because they each possessed very different personalities and characteristics that were intended to complement one another and provide the Warmaster with a wide array of different viewpoints. Each of these personalities accorded with the ancient Greek Hippocratic medical theory popular during the Middle Ages of the Four Humours or substances of the human body whose relative proportions and amounts shaped all physical and mental characteristics - blood (sanguine), yellow bile (choleric), black bile (melancholic), and phlegm (phlegmatic). A sanguine person is courageous and hopeful, a choleric one is angry and bad-tempered, a melancholic person is often despondent, depressed and irritable and a phlegmatic personality is one that is calm and unemotional. Abaddon possessed the Mournival's choleric personality, Aximand the melancholic, Torgaddon the sanguine and Loken the phlegmatic. Hastur Sejanus, whom Loken replaced in the Mournival, was said to have possessed all four humours in perfect balance, thus giving him the perfect human personality according to the Hippocratic theory.
The word Mournival, according to the Iterator Memed, was drawn from the ancient Franc (French) language of Terra and referred to a hand during a card game that included one of each of the four face cards, which was usually a winning hand. The origins of the Mournival are uncertain as the tradition either began soon after Horus was installed as the leader of the Luna Wolves Legion when the Great Crusade reached his homeworld of Cthonia or was an outgrowth of the informal warrior lodges that began within the Legion after their conquest of the world of Davin only 60 years before the start of the Horus Heresy. When the Heresy began, there had been 13 Luna Wolves in total who had been members of the Mournival, including the four final members before the Mournival was shattered at the start of the Heresy. After the Heresy began, the Mournival was brought back to full strength after the Battle of Dwell with two new members, such that 15 members of the XVI Legion had served within the body by the time its existence was brought to an end after the death of Horus at the Battle of Terra.
Whatever its origins, the primary duty of the Mournival was to advise Horus in all aspects of strategy, tactics, diplomacy and all other matters that concerned the Warmaster or the Luna Wolves Legion. The Mournival could be used to serve Horus' political needs at times when he dealt with the other Primarchs or other Imperial organisations like the Imperial Army, various Imperial Planetary Governors, the Council of Terra and the Adeptus Mechanicus. Every member of the Mournival had the helmet of his Power Armour marked with a phase of the moon imprinted on the helmet above the right eye. At the time of Garviel Loken's ascension to the Mournival, Abaddon wore the Full Moon, Aximand the Half Moon, Torgaddon the Gibbous Moon and Loken the New Moon that had also been the phase worn by his predecessor Hastur Sejanus.
After Horus' corruption by the Ruinous Powers of Chaos following his healing by the Chaos Cultists of the Serpent Lodge on Davin, the Mournival became divided. Abaddon and Horus Aximand gave themselves over completely to their beloved leader Horus and chose to follow him into the worship of the Chaos Gods, while Torgaddon and Loken remained loyal to the Emperor of Mankind. The Mournival was broken during the Battle of Istvaan III as the majority of the four Traitor Legions at Istvaan III turned on the Loyalist Space Marines who remained within their ranks, and Loken and Torgaddon faced off against Abaddon and Aximand just before Horus' 63rd Expeditionary Fleet began its final orbital bombardment of the Loyalists' positions and ended the battle. Loken and Torgaddon are currently believed to have died during that bombardment.
After the deaths of Garviel Loken and Tarik Torgaddon on Istvaan III, the remaining members, Abaddon and Aximand, debated who their replacements were to be before the attack on the Loyalist held planet of Dwell. After the successful invasion, Sergeant Grael Noctua of the 25th Warlocked Tactical Squad and Captain Falkus 'Widowmaker' Kibre of the Justaerin Terminator Squad became the successors of their Loyalist brothers.
Known Mournival Members
Below are the known members of the XVI Legion who were members of the Mournival in the approximate order they were initiated:
- Captain Berabaddon (Killed during the Great Crusade)
- Captain Litus (Killed during the Great Crusade)
- Captian Syrakul (Killed during the Great Crusade)
- Captain Janipur (Killed during the Great Crusade)
- Captain Hastur Sejanus (Killed on the world of Sixty-Three-Nineteen during the Great Crusade)
- First Captain Ezekyle Abaddon
- Captain Tarik Torgaddon (Killed by Horus Aximand on Istvaan III)
- Captain Horus Aximand
- Captain Garviel Loken
- Sergeant Grael Noctua
- Captain Falkus Kibre
In ancient Egyptian mythology, the god of kingship, Horus, had four sons, each with a different personality and nature who when combined made up the entirety of Horus' own soul. This is clearly very similar to the relationship between the Primarch Horus and his Mournival.