Editing Gene-seed (section)

===Primaris Organs===

{{Main|Primaris Marines}}
After [[Roboute Guilliman]] told [[Belisarius Cawl]] to make a next generation Space Marine, he ended up creating Marines that had an enhanced version of the Astartes Gene-Seed, which contained an extra three organs (possibly due to taking elements of the [[Adeptus Custodes|Custodes]] or even the Primarch creation process). While some have expressed concern of the project, some due to worries about how some of the mutations of some of Chapters with more exotic mutations and some due to the belief that the Emperor's work shouldn't be tampered with, Cawl claims that the Primaris Gene-seed is more stable than the regular Astartes gene-seed, with an estimated deviancy of .001% per generation. How true this claim might be is up for debate, but Cawl has created Space Wolves successor chapters that haven't immediately turned into Wulfen so it may have some truth in it. It's also worth noting that Cawl did ''something'' to make the Primaris Marines physically incapable of turning traitor. Guilliman's internal monologue in Dark Imperium reveals that he considers it an impossibility for Primarines to turn, unlike "the old breed". This has interesting implications about whether or not the Primaris marines truly have free will.

As of recent fluff updates/leaks, the new organs are as follows.

# The '''Sinew Coils''' essentially modify the muscle strands and makeup of the Primaris Marines, buffing their pecs and biceps to the 10th degree. Whilst one would assume it would resemble something from [[Wat|Inspector Gadget's coil legs]], the truth is....[[Derp|it is pretty much like that in function.]] These are reinforced coil-cables made of durable supermetals that are capable of contracting with incredible strength, making Primaris stronger and tougher than others. Even outside of their power armor, swinging a sword at a Primaris might just bounce off his hot and sweaty muscles because of these coil cables, and it amplifies his strength to the point where he can crush a human skull with his bare hands or bite through metal cable like it were jerky.
# The '''Magnificat''' may sound a [[Derp|bit lame,]] but its function is actually what makes the Primaris 'bigger, better, faster and stronger' than regular Astartes. It produces a mix of hormones that greatly enhance the effects of all of the other genetically engineered organs that float around in the Primaris. So every Primaris gets more bang for his genetic buck. Intriguingly, it's stated to be only half of another super-organ dubbed the '''Immortis Gland''' originally made for the Primarchs, but Cawl was only able to find the materials and genetic blueprints needed to make the right half; the information needed to make the left half had seemingly been erased. The function of the complete Immortis Gland is unknown, but given that its other name is "The God-Maker" and the fact that only the Primarchs are known to have the organ, it stands to follow that it is likely what amplifies their abilities to the level of demigods.
# The '''Belisarian Furnace''' is an organ that is named after [[Belisarius Cawl|the Galaxy's least humble Archmagos.]] This one is a last-chance fail-safe kind of thing. The Belisarian Furnace is an organ that activates when a Primaris is on death’s door, giving them a great burst of super-adrenaline (not the actual term) and boosted regeneration, but helping to keep them alive even at great cost, so that a Primaris can take out as many of the enemy as possible even as his flesh and bone rapidly regrow themselves. This allows fan-fic writers to create Hollywood-esque 'final pushes' without making it look stupid, which should make for some amazing last stands. It also appears to be vital for the Rubicon Primaris procedure intended to convert existing Space Marines into Primaris Space Marines, as the procedure temporarily kills the subject in its current form. The organ doesn't just activate during fights however ; the fluff has shown a Primaris actively trying to "calm down" and stop their Furnace activating whilst they were critically injured whilst they were being rescued as the resulting physical shock would finish them off.