Described as having classical features, Vespasian was one of the greatest warriors of the Emperor's children. Vespasian was noted by First Captain Julius Kaesoron as being controlled, graceful and utterly deadly. Warriors who followed Vespasian would take their lead from him in all things. As a role model he set an example of how best to achieve perfection through purity of purpose. Vespasian's strong moral values stood in stark contrast to his less virtuous counterpart, another Lord Commander of the III Legion, Eidolon.
Vespasian led the operations on Twenty-Eight Three, a planet also known as Laer during the campaign that would later be referred to as the Cleansing of Laeran. Unknown to the Emperor's Children, the Laer were worshippers of Chaos. After the Cleansing of Laeran, the corruption of Chaos began to spread throughout the Emperor's Children. Vespasian, staunchly adhering to his ethos, resisted the arrogance and hubris commonly found now in the legion. Ignorant to the existance of Chaos; over the course of weeks or months Vespasian consulted other like minded members of the legion, including the Second Company's captain Solomon Demeter, about his growing concerns.
Vespasian was present on Tarsus, an Eldar maiden world, during a meeting with Eldrad Ulthran — Farseer of the Ulthwé Craftworld. During this conference, the Eldar warned Fulgrim and his delegation of Horus' fall to Chaos and of the future rebellion. Fulgrim utterly rejected the accusations of the Eldar and a battle concluded the meeting. Vespasian reluctantly destroyed Tarsus and the rest of the maiden worlds the expedition had recently encountered with virus bombs after being ordered by Fulgrim. Weeks later, the 28th Expedition rendezvoused with Horus' 63rd Expedition as ordered by the Council of Terra. Fulgrim had been ordered to inquire into reports the Council had received about the conduct of the 63rd Expedition and information of the Warmaster's grievous injuries suffered on a moon of Davin. Vespasian was not included in the delegation that met with Horus further underlining the growing rift between Vespasian and his Primarch.
Vespasian met his end after an operation conducted by the III Legion to cleanse Deep Orbital Station DS109 in the Callinedes system of an Ork infestation. Having been unusually denied a meeting with Fulgrim after numerous requests, Vespasian felt obliged to act after he observed Solomon Demeter's 2nd Company intentionally abandoned. Seizing the moment, Vespasian confronted Fulgrim in his staterooms over the growing rot and decay of the ideals that their Legion was founded on. To his horror Vespasian discovered too late the influence Chaos held over his Primarch. It was then that Fulgrim murdered Vespasian by stabbing him in the neck with Anathame.
- 1: Fulgrim (Novel) by Graham McNeill