Editing Horus Heresy (section)

===Magnus the Red: Master of Prospero===
Depicts the unlikely friendship between Magnus and old Pert with a joint venture between their legions to evacuate a planet that's getting torn apart by accelerated magnetic polarity shifts. Things go wrong on the planet due to totally not Chaos cult nonsense, and it does a decent job of showing Magnus' flaws, specifically his inability to leave things that have "do not fuck with this" written on them alone; something Pert tries and fails at making him understand. Crucially it's set early enough in the Crusade that the use of psychic powers by Astartes is uncommon and the Thousand Sons basically have to keep a lid on how powerful they really are. They do not succeed.

The original colonists of Morningstar survived by rounding up all the psykers into their seed ship and splitting them from their psychic powers throne room of the emperor style. However since they didn't dissipate these psychic powers, the souls of the psykers just floated around inside the ship until they joined up into a single entity. When their jailers realized what was happening, they ran and sealed the ship but the psychic gestalt had already infected their minds with a doomsday meme, resulting in the shenanigans that Magnus and Pert arrive to. The entire Morningstar government fell victim to this meme and built a continent sized machine to destroy their planet which Pert & Magnus somehow didn't notice. The surviving natives of Morningstar are obliterated in space to stop the meme from spreading, and shortly before the Siege of Terra Magnus Pókeballs the psychic gestalt from its prison in the ruins of Prospero into his book so he can use it to get past the Emperor's psychic shield.