Amon Tauromachian - History: Amon Tauromachian was present at the Triumph of Ullanor, where Horus Lupercal was invested by the Emperor with the title of Imperial Warmaster and command over all the Imperium's armed forces. While he manned a checkpoint alongside a fellow Custodian, Haedo Venator, as well as seven Null-Maidens of the Silent Sisterhood, the Thousand Sons Primarch Magnus the Red was impressed by Amon's stoicism and dedication and predicted that great things lay ahead for him.Many Terran years before the start of the Heresy, Amon was also present at the Council of Nikaea to watch over the trial of the Crimson King for his use of sorcery. Whilst protecting Kasper Hawser, a skjald of the Space Wolves, Amon was attacked by a minion of Chaos in the disguise of a Thousand Sons Space Marine, but managed to survive the encounter thanks to the efforts of the Space Wolves Astartes.Amon was later charged with protecting the Emperor when Terra began the process of fortification to withstand the coming assault on the Throneworld by the Warmaster Horus and his Traitor Legions. After news of Horus' betrayal at Isstvan III reached Terra, Amon was tasked with taking part in the "Blood Games," a rite all Custodians endured and one which set them against the formidable defences of the Imperial Palace in the hope of improving the Custodians' defence of the Emperor through the exposure of flaws in His protection. After ten solar months, and with great difficulty, Amon was able to successfully infiltrate the Imperial Palace and came within striking distance of his target (presumably the Emperor).Following his success in the Blood Games, Amon Tauromachian and a fellow Custodian Haedo Emankon were sent on a dangerous mission by Captain-General Constantin Valdor, Chief Custodian of the Legio Custodes, to gather incriminating evidence on a member of the government of unified Terra, Pherom Sichar of Hy Brasil, who was suspected of treason against the Emperor.When Amon went to confront Sichar, the Imperial Fists Primarch Rogal Dorn intervened on Sichar's behalf and explained to the Custodians that he was, in fact, an Imperial double-agent. But due to Amon's interference, Sichar's cover was now blown. Audaciously, Amon suggested to the primarch that in the future, all Imperial organisations should share such intelligence to avoid such situations from reoccurring.It was later revealed that one of Sichar's bodyguards -- a member of the illustrious Imperial Army regiment known as the Lucifer Blacks -- was an actual agent of the Warmaster. In a suicide attack, this agent detonated a bomb that killed Sichar. He then attempted to set off another bomb so that it would destroy Planalto Central, one of Hy Brasil's largest hive cities, but was stopped by the timely intervention of Amon.During the Siege of Terra Amon was tasked by Constantin Valdor with investigating suspected Daemonic activity within the Imperial Palace. His investigation led him into the refugee camps of the Inner Palace, where he met Euphrati Keeler, the survivor of Isstvan III who had become a living saint to those who believed in the cult of Emperor-worship.Amon expressed his distrust concerning the intentions of the future saint and her followers, fearful of the fanaticism that such religious beliefs always portended, but was told by Malcador the Sigillite, the Regent of Terra, to tolerate their presence in order to potentially use their faith as a weapon to combat the powers of the Warp.However the Nurglish Daemon Cor'bax Utterblight was ultimately unleashed in the palace through the machinations of those loyal to Horus, and this intrusion into realspace was accompanied by a swarm of Emperor-worshippers who had been possessed by Daemons. With the aid of Keeler and Malcador, Amon was able to defeat Utterblight. For his great deeds and to indicate his future status as a warden of Keeler's cult of Emperor-worshippers, Malcador recommended that Constantin Valdor award Amon a new name as was the custom of the Custodians to mark great events in their lives. Valdor did so, and granted Amon the new name of Longinus.Later during the Siege of Terra, Amon was assigned to oversee Keeler as she resumed her original occupation as a Remembrancer and interviewed the infamous criminal Basilio Fo. When Fo revealed the existence of a contagion capable of killing not only the Traitor primarchs but all Space Marines, Amon agreed with Keeler's assessment that the data should be provided to Rogal Dorn, the primarch who was the Praetorian of Terra and was overseeing the Throneworld's defence. Later Amon and Keeler again met with Fo, and this time recorded all of his comments concerning the existence and capabilities of this transhuman virus. Amon  was later tasked with hunting down Fo when he escaped from Imperial custody, but the criminal eluded him, which forced Valdor to apprehend him personally.