The Dornian Heresy - The Bolter and Chainsword

Pre-Heresy:
The Seeds of Destruction
In the closing years of the thirty-first
millennium, the Emperor‟s Great
Crusade to reunite humanity under His
banner was continuing apace. Vast
expeditionary armies, spearheaded by
His primarch sons, surged out across
the galaxy, bringing enlightenment and
compliance wherever they went. The
future seemed assured, and during a
mighty celebration on Ullanor, the
Emperor announced that He would
return to Terra, and that Horus,
Primarch of the Luna Wolves would
command the Great Crusade in His
stead. Some say that this event was
where the seeds of disaffection were
planted amongst the primarchs, with
one of their number being so publicly
elevated above the rest. In truth, the rot
had started long before.
After the Ullanor Declaration, the
cracks began to appear. Bitter disputes
over the use of psychic powers came to
a head at Nikaea, with legions
vehemently split over their use. The
Emperor's final ruling, and the special
concessions he gave to the Thousand
Sons, enraged Russ and his Space
Wolves. They saw Nikaea as a terrible
mistake, and secretly vowed to save the
Emperor from himself.
On the feral world of Davin,
Warmaster Horus was struck down by
a mysterious contagion which baffled
the finest of the legion‟s apothecaries.
During his recovery, Horus attended an
initiation ceremony of one of Davin‟s
primitive warrior lodges, after which
the Warmaster‟s condition dramatically
worsened to critical. That a primarch
could succumb to any natural pathogen
should have given a hint that what
happened in the halls of the Knife of
Bone involved the supernatural. It was
in fact an act of possession by a
powerful warp entity, although at the
time the concept of the daemonic was
widely regarded as errant superstition.
Only with the aid of the psychic might
of the blind Primarch of the Thousand
Sons, and spiritual counselling from
Chaplain Erebus of the Word Bearers,
could the entity finally be cast out. So,
with the Warmaster having escaped
their snare, the Ruinous Powers turned
their attentions elsewhere.
The ordeal revealed to the Warmaster
the true dangers of Chaos - a power so
great that even he and his fellow
primarchs were not immune to its
corrupting touch. Horus was severely
weakened by the events of Davin, and
out of position to deal with what was to
come. First, Curze of the Night Lords
attacked Rogal Dorn, before going on
the run with his legion. Worse still,
word came from the galactic east that
Guilliman had declared independence
from the Imperium, claiming dominion
over a massive region of space that he
called „Ultramar Segmentum‟.
Even as the Imperial forces assembled
to confront the Ultramarines, terrible
news came from Prospero that the
Space Wolves had fallen upon the
homeworld of the Thousand Sons.
With the Warmaster
having escaped their
snare, the Ruinous
Powers turned their
attentions elsewhere...
They proclaimed that Magnus was
mired in foul sorcery, and sought to
destroy them before they could betray
the Emperor. With the dream of
mankind coming apart at the seams, the
legions came into high orbit around
Istvaan V.
Betrayal at Istvaan
Guilliman and the lion's share of his
massive Ultramarines Legion were
identified as being present at his
newest conquest, the fifth planet of the
Istvaan system. This was set to be the
place that the Imperium would crush
the rebellious primarch and his dreams
of an independent domain.
With Horus still recovering after
Davin, Rogal Dorn used his position as
the Emperor‟s Praetorian to take
command of the forces congregating
around Istvaan. The Ultramarines were
by far the most numerous legion, in
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large part due to Guilliman‟s
organisational skills, and so a suitably
overwhelming force was assembled in
opposition. Dorn summoned the might
of nearly half the Emperor‟s legions to
the task, although offers of forces from
long-time rival, Perturabo of the Iron
Warriors, were pointedly rebuffed.
Such was the size of the task of
bringing the secessionist realm back to
heel that two whole legions were sent
deep into Ultramar Segmentum. The
Alpha Legion, never friends of the
Ultramarines, were to infiltrate and
undermine the rebel worlds, while the
religious zealots of the Word Bearers
used a more direct approach: bringing
the light of the Emperor to the very
core of Guilliman‟s powerbase on the
Eastern Fringe.
The first to join the Imperial Fist fleet
outside the Istvaan system were the
Raven Guard and the increasingly
insular and secretive marines of the
Iron Hands. These were closely
followed by the Salamanders, led by
their burned, bitter primarch. Shortly
after came the Emperor‟s Children,
fresh from extinguishing the xenos
threat on the planet Laer. The events of
that campaign had affected Fulgrim
deeply, and on arrival he declared that
his legion had achieved the pinnacle of
the Emperor‟s „Perfection‟. The relish
with which they embraced the chance
to prove their superiority over other
Astartes bordered on the unseemly.
Then, in precise, well-ordered
formation, came Angron‟s World
Eaters. Long-gone was the savage
gladiator mentality of Angron‟s early
years – his first meeting with the
Emperor on the slopes of Fedan Mhor
had seen him reject his former brutality
as the impetuosity of youth. The final
force to break from the warp was
composed of vessels belonging to the
Dark Angels, whose arrival came as a
surprise to those assembled. Lion
El'Jonson himself had sent word that
they would not be able to return in time
from their assignment among the
Ghoul Stars. It was explained that the
force had arrived directly from their
homeworld of Caliban, and Luther, the