Hraxis succeeded his mentor Inquisitor Patricex as Grand Inquisitor of the sector during the 24th Agrippa war.

During the 26th Agrippa war the Inquisitor took a more prominent role in the direction of the crusade after scandals and High Lord Admiral Goethe's death early in the operation.

He garnered a reputation of being a stubborn opponent and somewhat fanatical (bordering on unreasonable) in his dedication to the Imperium's cause.

For example, Hraxis stirred the pot when he ordered an impulsive advance into Eldar territory during the Scylla crusade despite protests from Admiral Kitchener.

He also ordered the landing on the dessert world of Kali without Naval support. A notion most Imperial strategist critisised at the time. However, his faith and determination proved to be a strong motivator for the doomed troops of the planet and without their hold the later success on Kali would never had happened

Following the Kali war Hraxis guided both his resources and the Council of Houses to blow open a sinister plot that proved the Cardinal Duke Thrackos was a traitor. Forcing the Cardinal Duke to flee, Hraxis led a bloodless coup in the power vacuum that followed the Duke's departure. However, Hraxis was killed by an Imperial Assassin shortly after taking the reigns of power.