Leandros - Liberation of Graia: Leandros was the newest member of Captain Demetrian Titus' Command Squad during the Liberation of Graia, after the Forge World was invaded by the Ork WAAAGH! of Warlord Grimskull. The Ultramarines 2nd Company's fleet came under attack by the Orks during their deployment to Graia, forcing many of the Ultramarines to deploy to the planet's surface using Jump Packs.This chaotic deployment led the Ultramarines of the company to be separated, but Leandros soon regrouped with Titus and their fellow command squad member Veteran Sergeant Sidonus, Titus' closest friend and confidante. The three fought beside 2nd Lieutenant Mira's 203rd Cadian Regiment against the Orks, but Leandros thought little of the guardsmen. His ascension to become a transhuman Space Marine had caused him to lose his Human perspective and treat mortals with contempt for their physical and mental weaknesses. Leandros was especially patronising to the surviving guardsmen he encountered on Graia. In the course of defending the Forge World alongside the Astra Militarum forces, Titus' squad crossed paths with Inquisitor Drogan.The Inquisitor explained that he was on Graia because he had sought to develeop a new weapon powered by the energies of the Warp called the Psychic Scourge, and he now required the Space Marines' help in defending it. Titus, Sidonus and Leandros succeeded in saving the Psychic Scourge from capture by the Orks, though in the process Titus was forced to hold the weapon. This surprised Drogan, however, as he believed that anyone who made physical contact with the weapon should be slain by it as the Scourge was empowered by the unpredictable energies of the Warp.Leandros made note of this anomaly, which raised suspicions in his mind as to why Titus had been able to survive exposure to Warp energies with no ill effects. Titus explained that he did not know why he had proven immune, but ordered Leandros and Sidonus to move on before the Orks attacked them again. Leandros reluctantly dropped the matter, and the Ultramarines escorted the weapon and Drogan to another base where it could be used. In doing so, Drogan hoped the weapon could be used to defeat Grimskull's invasion, since the Psychic Scourge had been designed to destroy xenos species based on the resonance of their psychic signatures within the Immaterium.However when the Psychic Scourge was finally activated to be used against the Orks, instead of killing Greenskins it actually opened a Warp rift above Graia that allowed the Sorcerer Lord Nemeroth, his Chosen of Nemeroth warband of Heretic Astartes and numerous Daemon allies to invade Graia. It was revealed that Inquisitor Drogan had actually been slain before he made contact with Titus' group and had been possessed by a Daemon in service to Nemeroth, which had essentially used him as an undead puppet.Before the three Ultramarines could be slain by the newly arrived Nemeroth, however, the Warboss Grimskull attacked the sorcerer and the Ultramarines were able to use the distraction to reclaim control of the Psychic Scourge. Under Titus' orders, the group used the psychic weapon to empower the Imperial Warlord-class Titan Invictus, which fired upon the Warp rift and weakened it.Afterwards, Titus gave the crucial power source of the Psychic Scourge to Sidonus and ordered the Veteran sergeant to take it to their strike cruiser Fury of Descent for safekeeping from the forces of Chaos. Titus and Leandros then kept Nemeroth's forces at bay while Sidonus raced towards a landing pad to wait for an aircraft to evacuate him. However, before he could be evacuated, Sidonus was killed by Nemeroth who teleported behind the sergeant and impaled him on his Lightning Claws. Titus and Leandros were unable to save Sidonus before he was killed and Nemeroth escaped with the power source.A vengeful Titus commanded Leandros to safeguard Sidonus' body until an Apothecary arrived to extract his gene-seed, and then join the Imperial counter-attack against the invaders. Titus planned to hunt down and kill Nemeroth before the sorcerer could use the power source to draw enough Warp energy into himself to become a Daemon Prince. Leandros vehemently disagreed with this because he believed Titus' course of action was little more than suicide or worse, would result in aiding the sorcerer's plans.Leandros explained that Titus had shown repeated resistance to the power of the Warp since Nemeroth had invaded Graia. This was an anomaly that  the sorcerer was aware of and Nemeroth had become interested in Titus' ability. Though Leandros denied fearing that Titus would fall to heresy, he believed whatever was causing Titus' resistance would ultimately only aid the sorcerer. Titus disregarded Leandros' concerns and insisted that he was in no danger of betraying the Emperor, before leaving Leandros behind to seek out and confront Nemeroth.However Leandros' continued concerns about Titus' Warp immunity led him to become convinced that Titus had already been corrupted by Chaos. He  made contact with the Inquisition, explained what he had witnessed and claimed that Titus had become a Heretic. Meanwhile, Titus succeeded in slaying Nemeroth and closing the Warp rift, as more Imperial reinforcements from the Black Templars Chapter, led by Inquisitor Thrax, arrived on-planet.Despite his victory ending the threat to Graia, Leandros' charge of heresy had to be investigated, and so Titus was taken into custody by Thrax and his retinue of Black Templars. Before he was escorted away, however, Leandros told Titus that the prescriptions of the Codex Astartes left no doubt that his captain was a Heretic. No one who was not tainted by Chaos could resist the power of the Warp as Titus had done.Titus shook his head sadly at his young protege and explained that the Codex was only a set of rules from which Space Marines should seek guidance on the path to honour. Yet it was how each Astartes conducted themselves within those guidelines that was the true test of an Astartes' worth. A test, Titus concluded, that Leandros had ultimately failed.Titus then boarded the Inquisitor's Thunderhawk. Leandros would not see his former mentor again for over a standard century.