A military formation developed in parallel with the Legiones Skitarii during the Dark Age of Technology, the Secutarii were created as the honor guard and protectors of the Titan Legions. The Secutarii have a number of roles, the first and most important of which is to protect a Titan from close-range swarms of enemy infantry. Their second duty is to advance in the wake of a Titan's path and destroy any surviving enemies and secure the field. Their third role is to act as escorts for Magos Autokratoris Tech-Priests as they go about their work. In this role, they frequently defend the Titan's force landing fields and supply lines as well as secure the wrecks of downed Titan engines.
The Secutarii are similar to the Skitarii and undergo a similar process of cybernetic augmentation, with the vast majority of their organs and tissues modified or replaced with circuit, bio-plastic, and metal. One of their most notable bionic implants is the Kyropatris Field Generator.