A member of Abaddon's inner circle, Vex Machinator's true name is a lost secret. He is instead named for his actions, as he brings vexation to all who approach him. He feeds on bitter discord of friends and foe alike and leaves a corrupting Scrapcode aura that corrupts all Machine Spirits in his presence. As he rides into war, orders go unheard and unheeded and battle plans unravel into discord. Outside of battle, his chaotic aura is used to undo those who would conspire against the Despoiler, such as foiling the plot of the Daemon Prince Shamha Ygra-Thrysh. It is difficult to find an agent of Chaos that is more roundly hated.
Abaddon deployed the Vex Machinator during the War of Beasts on Vigilus. When he led a charge of Bloodcrushers and Daemon Engines against the Cadians at Tzimitria Breach, the previously disciplined troops could not focus their fire as they had been trained. They paid for their mistake with their lives.