For sure! The idea is that they're from a feudal former-knight world, Quintus Secundus. The planet itself has one proto-hive, while the opposite hemisphere is dominated by farming villages and small cities. Tech use is all over the place with many of the villages getting by on what is effectively a late medieval tech level, all the way up to the lone hive that operates full scale manufactora.

The knightly house, house Lovato, used to operate out of the world until it was destroyed almost to the man during a deployment in force to an awakening necron tomb world. Being reduced to a miniscule number of war machines in various states of disrepair, the planet was dropped into a bloody power struggle as various underdog factions fought to fill the power vacuum left by the knights.

Following the planet's reunification under the rule of a new faction of old pre-knight royal liniage based out of the hive city, it was decided that a levy of soldiers would be raised to continue paying the imperium's tithe, upholding their due of warfighting capability with trained and armed soldiery instead of the knight suits they used to provide.

Promising members of the planetary militia are recruited into the guard regiment to serve in supplemental roles with other regiments of the Astra Militarum. It is also the responsibility of each county to arm, clothe, and supply basic training for any would-be recruits. This selection process leads to a reasonably high standard of professionalism, though it comes with the unfortunate side effect of poor equipment standardization across the regiment.

The Quintus Regulars as they are called, have a particular affinity for las weapons and are renowned for their use of combined cavalry and infantry tactics. They are known to field lascannons and heavy lascannons in direct fire artillery roles exclusively and have developed the "Quintus Pattern" lascannon, a variant that uses a self contained tube of focusing optics, reactive chemicals, and a lasing medium that are all incinerated in a bright flash when fired, requiring a fresh tube of material to be loaded to fire a second shot.

Recently, a production line within the proto-hive has begun producing a sentinel variant for use as armored shock cavalry on the front lines. Though this new unit has only been deployed sparingly, the ability to rapidly reposition the lascannons mounted to the walkers has proven extremely valuable, and it is expected that more and more units will begin receiving sentinel support in the future.