They were not just guards but an intelligence agency, employing speculatores to spy on citizens and dissenters alike.
They were the shadow behind the throne, the only armed force allowed within the sacred walls of Rome. While they were sworn to protect the Emperor, they often became the ones who decided who lived to wear the purple. Praetorians
Unlike the mindless Warriors, Praetorians are highly intelligent. They arrive unannounced on battlefields, striking with gravity-defying jump packs to execute "lesser" races who have trespassed on Necron territory. The Praetorian Guard (Warhammer 40k: Astra Militarum) Creative Micro-Fiction "Hold the line, lads! For Praetoria and the Emperor!" They were not just guards but an intelligence