Editing Magnus the Red (section)

===Fragments of Magnus===
Unknown to everyone save perhaps Tzeentch himself and Magnus' inner circle, the teleportation of Magnus to the Planet of the Sorcerers at Prospero had the side effect of splitting the Primarch's soul into a large number of lesser fragments, many of which might not have even been aware of the split and believed that they truly were Magnus the Red.
The actual number of fragments is not known exactly, but an allegorical representation of them showed a broken statue of a bird, with some fragments being as small as grains of dirt though the largest piece was definitely recognisable as parts of a bird.

*The fragment that travelled to the Planet of Sorcerers was the greatest shard of Magnus' soul, although upon its arrival it was nothing like the Primarch or the daemon-prince Magnus that are well known to the 40k universe. Although it appeared to be Magnus the Red, it has the mindset of a senile old man who was dying. This Magnus barely knew where or when he was at the best of times and was constantly forgetting who his companions were or what Leman Russ had done to him or his Legion. This shard of Magnus spent centuries ''(of warptime, so practically no time at all in realspace)'' fleeing his memories through the warp while being chased by his equerry [[Amon]] who was trying to bring him back. In a moment of lucidity he was the first to reveal that his soul had been shattered, but only by reliving the battle of Prospero did the Thousand Sons have an idea of where the largest shards went to, so Ahriman led a quest to reclaim them and restore his Primarch, gathering enough to amalgamate the Crimson King.
**'''The Crimson King''', the Daemon-Primarch of Tzeentch as he exists in the present, was the recombination of several shards as the Horus Heresy went on and by far the most powerful of the Magnus-fragments. His first act was to declare that he would join Horus' rebellion and lay siege to Terra to reclaim his greatest fragment ''(Janus)''. He would exile Ahriman for the first failed Rubric, would later instigate the Battle of the Fang and then spend the next ten thousand years being a dick, eventually fouling up Ahriman's second Rubric but achieving near-complete unification of all the shards. Unsurprisingly, the only parts that weren't reunited with The Crimson King were all the ones which embodied Magnus' noblest, most selfless qualities.
*'''"Magnus"''' (as the father of the Thousand Sons and '''author of the [[Book of Magnus]]''') was the portion of Magnus that seemed to care the most about his legionaries and of his son Ahriman in particular. Much diminished, he remained behind the scenes for centuries attempting to subvert the Daemon-Primarch and guide his son Ahriman ''(and by extension the Legion)'' back to greatness and presumably ''(at a push)'' back onto the path the Emperor intended for them. It was he who inspired Ahriman to attempt the original Rubric in the first instance since it was actually his own spell. "Magnus" (the father) knew that it would fail, but the flesh-change was overcoming the legion anyway, and the failed attempt would provide Ahriman with both the time and the conviction to eventually complete his great work and attempt a second rubric by pooling his own resources with knowledge gleaned from various other fragments, including the Athenaeum of Kallimakus. It was also he who influenced Amon's dreams to seek out Ahriman to kill him and undo the Rubric and end their brothers' agony. While this shard of Magnus admitted he sacrificed Amon to re-motivate Ahriman to do the second Rubric, he believed it was the proper course of action to save their legion and make Magnus whole without the Crimson King's influence. The end result may have actually cured his legion & father by reuniting the broken primarch and reversing the flesh-change, and allow the personality of "Magnus" (the father) to assert control over the united fragments and redeem himself. However, even if it had worked the interference of the Crimson King would have caused it to destroy the fragments instead. Ultimately, it faded into oblivion rather than allow the Crimson King to reabsorb it.
*The great library of knowledge: the '''Athenaeum of Kallimakus''' actually was a fragment of sorts, but not able to act independently, only providing a link to the stream of consciousness of the original Magnus the Red. However the Athenaeum was corrupted after being discovered by the Crimson King, who attempted to insinuate his own mind into the thought-stream and attempt to assert control over Ahriman's second rubric result. His dipping in and out of the stream introduced flaws into the spell which would still have allowed the Thousand Sons to regain their flesh but would have destroyed all the fragments of Magnus in the process.
*A lesser shard was hidden within the ashes of '''Kallista Eris''' that was carried around in an urn for years yet was completely oblivious to the [[Sisters of Silence]], the [[Thousand Sons]] and one of the [[Knights-Errant]], beneath whom the urn had passed almost completely unnoticed. It was only when proximity to the shard of Aghoru that it awakened, although its motivations are largely unknown because it seemed to be operating under the orders of the other shard until it fused with it.
*One fragment remained on Prospero, representing his acceptance of the Emperor's judgement against him, this Magnus was stuck in limbo and meditation for a while, until [[Jaghatai Khan]] rocked up to Prospero to find out what had happened. This fragment served up a nice big info-dump and urged him to pick a side in the war, and in return Jaghatai banished him from Prospero.
*Another became a daemon of vengeance that was unwittingly passed from host to host ''(It was thought to be a normal daemon, no-one realised it was a actually a shard of Magnus)''. It eventually came to inhabit the body of a renegade space marine called Astraeos. This shard saw the Crimson King as a usurper but was eventually consumed after a very quick battle with the Crimson King following the failed second Rubric.
*One returned to Nikaea and represented the part inside of Magnus that died when the Emperor made his pronouncement against him. This shard was literally a corpse being clawed at by daemonic hands.
*One represented his warrior aspect and was found on the planet Aghoru seemingly waiting to duel whoever showed up. It held off a [[Knights-Errant|Knight-Errant]], a Rune Priest, a small squad of space wolves, a bunch of cyber automata and a freaking Samurai at the same time without any overt use of psychic power until it was bound into the body of a mortal. Interestingly, this shard had no intention of reuniting with the greater because Magnus was not actually known for his battle-prowess, so this fragment would rather have remained and made a name for himself equal to Angron or the Lion, nonetheless it later absorbed the shard of Kallista Eris into itself and was absorbed in turn into the Crimson King anyway.
*Another fragment representing Magnus' desire to seek knowledge for the sake of its acquisition. It was thrust into Terra's past and inhabited the body of King Kadmus, one of the Emperor's enemies, requiring Ahriman to time-travel in order to reclaim it.
*One fragment remained on Terra and was fused by [[Malcador]] to '''Revuel Arvida''', inadvertently creating an entity known as '''Ianius''' ''(Janus)''. Yes, the same Janus that would become the first Supreme Grand Master of the [[Grey Knights]]. It is believed that this fragment embodied Magnus' nobility and connection to the Emperor.
*From the Prologue and Epilogue there may very well have been a second fragment of Magnus that resided on Terra and was known to Malcador and Rogal Dorn. But where Revuel Arvida housed a shard in his flesh and became Ianius who remained ostensibly Astartes, this shard was fully formed ''(an oversized giant with crimson skin)'' and housed within a villa hidden deep beneath the crust of Terra from where he narrates the novel ''Crimson King''. This fragment took upon himself the role of archivist of the Horus Heresy, and pinned his hopes for the future on some all-seeing device in the warp called ''The Orrery''. Perhaps building it with the help of his equerry Amon while he was chasing a different shard of his emotional father through time and space via the warp, or by completing his own orrery separately, or simply referring to the one the Crimson King made. It could then be this shard of Magnus who rescued the ship carrying the body of Vulkan and guided it back to Nocturne so his brother could be resurrected.
**It may also yet be Janus speaking from an earlier time period before his binding, who knows? The warp is confusing enough without it being inhabited by multiple aspects of the same guy over different time periods.
**Regardless of whether it is Janus or an entirely separate fragment, one of the Terran shards was believed by the Crimson King to be the first and greatest fragment of the Soul of Magnus and so he was willing to lay siege to Terra to reclaim it, even going so far as name it his sole reason for joining Horus's side of the war.

By the novel Ahriman Unchanged, Ahriman would complete his second Rubric and attempt to cast it on [[Sortiarius]]. Unfortunately the Rubric was not completed as Ahriman was interrupted by a member of the Thousand Sons who knew that the outcome would result in Magnus' annihilation and wanted to avoid it, so he seized control of the magical energy before Ahriman could finish the spell and obliterate their father. This resulted in several of the fragments reuniting into the Daemon Primarch Crimson King and increasing his share of power to a state indistinguishable from that which he possessed as a complete being. The aspect of vengeance: Astraeos would be the Crimson King's first victim and be absorbed almost immediately, while Magnus (the father) would fade away into nothing after having hung on for so many centuries only to fail in his objectives to lay claim to the soul of Magnus or heal his Legion- all it could do was deny the Crimson King what little power it still possessed.
*Although he [[Just as Planned|might have actually succeeded]], in by failing to complete the second Rubric, as a side effect Ahriman was uncoupled from his destiny and now "free" from divine manipulations, something that Magnus ''(the Father)'' had wished for all of his sons. But even then Ahriman ultimately continued to serve Tzeentch of his own will, so how much of a victory this may have been is up for debate.

This means that while Daemon-Primarch Magnus at the turn of the 41st millennium is in his most complete state and the various schemes of the separated fragments have been put to rest, Magnus is still not "whole" and likely will never return to his original state due to the loss of significant fragments; in particular, the evaporated essence of the compassionate father figure who set the rubric in motion, and probably the missing nobility of Janus, who died centuries earlier in service to the [[Grey Knights]]. At this point it can be assumed that Tzeentch filled in the remaining parts with himself, cementing Magnus' state as a Daemon Prince and eliminating any chance of his redemption.