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Roboute Guilliman continued to lead the Ultramarines for the next hundred years until he and his warriors fought against the traitor Primarch, Fulgrim, and the Emperor's Children on the world of Thessala. Fulgrim had changed beyond all recognition. The noble man he had once been had died long ago upon his elevation to a Daemon Prince of Slaanesh and now he was corrupt beyond words. His serpentine body was multi-armed and each taloned fist carried an envenomed rapier. Billowing clouds of heady musk enveloped the Primarchs as they met in single combat on the red fields of Thessala. None who were present on that day can say for sure what happened, yet when the cloying musks cleared, the Emperor's Children were gone and Roboute Guilliman lay unmoving, a single bright slash of blood across his throat. Not even the Primarch's god-like physique could halt the spread of Fulgrim's poison and, as Guilliman died, the Apothecaries set up a stasis field and transported their leader back to Macragge. To this day, Roboute Guilliman remains entombed within the stasis field, held immobile on his marble throne in the Temple of Correction on Macragge. There are those who claim that the Primarch's wounds are healing, but this is clearly impossible within the time-locked bubble of a stasis field. Despite this self-evident fact, many believe such tales and await the time when Guilliman will be fully recovered.
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чушь, в бэке чётко прописано, что Гиллиман стоял во главе Ультры ещё 100 лет после Второго Основания, которое произошло в М31