Kathaphron Grav Clade YT133 and YT137, Kataphron Destroyers

Magos Linval values Grav weaponry above all else, as it exemplifies his personal principles: use the opponent's might against them. For this reason the fast mayority of the Forge World's Kataphron servitors are of the Destroyer variety, armed with Heavy Grav Cannons.

Brotherhood of Bolts, Corpuscarii Electro-Priests

The fanatics known as the Brotherhood of Bolts are extremists even by the standard of fellow Corpuscarii Electro-Priests. Total disregard for their own well-being, the Brotherhood of Bolts is constantly at the forefront of the Forge World's battles.

Both Magos Linval and Logis Stahlman don't care for the Electro-Priests either way and just let them be, a fact that suits the Corpuscarii quite well.

Maniple Delta Gnux, Kastelan robots

Acting as the personal bodyguards of Logis Stahlman, the Maniple Delta Gnux is infamous among Hephaes' enemies. The orks have come to call them “da Nob Kans”, as they remind them of their own Killer Kans but with a more … regal demeanor.

Among the heretics that have tried to conquer Hephaes, they are known as “Wrath of Steel”. They are equipped with Power Fists and Incendine Combustors and are part of the vanguard of the Cult army.

Chief Datasmith Raymoon Steric

A true servant of the Omnissiah, Chief Datasmith Steric's mastery of the Binary language is thus that few of his colleagues can follow his monologues without pausing to grasph the meaning.

No real ambition of his own, the Chief Datasmith is content with his current task, feeling a deep kinship  to the machines he commands: two Kastelan robots armed with Heavy Phosphor Blasters.

Forge Lord Logis Stahlman, Tech Priest Dominus

Opposed to Magos Linval, Logis Stahlman would see machines win the final victory in the battle for the galaxy. He simply condones the Imperium at large, but doesn't actively support it. Contrary to most of his colleagues, Logis Stahlman prefers to get into the thick of it instead of controlling his forces from the sidelines.

He personally commands the Maniple Delta Gnux, comprising of up to six Kastelan robots. Although as of yet he wasn't successful in granting the Kastelans true autonomy in choosing their battle protocol, he claims to be able to scry their intention and implement the desired battle protocol accordingly.

Forge Lord Magos Torx Linval, Tech Priest Dominus

One of two rivaling Tech Priests on Hephaes, Magos Linval is a loyal ally to the Imperium. Although he left his humanity far behind him, all his actions are guided by the welfare of the Imperium and its Emperor, whom he considers to be the Omnissiah made flesh. Magos Linval is responsible for the Forge World's good relationship with the local Imperial Fists, although there is no formal partnership between Hephaes and the Imperial Fists.

When the Cult Mechanicus joins forces with the Forge World's Skitarii, Magos Linval is usually accompanied by a Skitarii Vanguard squads of the Omicron Theta Vexillation.

Baron Uther Sagramore, Imperial Knight

There is no Knight World in the Audacia Sector, yet the Adeptus Mechanicus faction has access to a small detachment, sent by House Taranis, loyal to the priesthood of Mars. This detachment is permanently assigned to Hephaes, and Baron Uther Sagramore is the commander of this detachment. His non-sanctioned title of “Guardian of the Forge” makes him the inofficial fifth member of Taranis' Exalted Court, but because he's stationed far from Mars, this title is purely honorific, solely bestowed on him to designate him as the leader of the detachment.
Like most Knight Barons, Sagramore leads from the front, fighting more battles for the priesthood of Hephaes than any other Knight under his command, partly because his Knight, the Furious Flame, is always on the Forge World's priority list when it comes to repairs and maintainance.