ComStar's internal and external security force, ROM (an acronym whose meaning has been lost to time) has a reputation as among the most elite intelligence agencies in Inner Sphere. After the ComStar Schism, both the secular ComStar and the Word of Blake maintained their own versions of ROM.
Formed in 2811 by ComStar founder Jerome Blake to help prevent leakage of technological information to the outside and to help thwart defection of ComStar personnel to the Successor States, this secret intelligence network would locate threats to ComStar and eliminate them before any damage was done. As per to Blake's proposal, operatives would work as undercover agents within the ranks of ComStar's technicians, as well as posing as citizens. Fear of ROM helped to ensure the quick adoption of the increasing mysticism of the ComStar Order by even its most skeptical members.
Due to the actions of the more militant and mystical Primuses that followed Blake, ROM also engaged in an extensive covert war to cripple technological advancement of the Inner Sphere outside of the halls of ComStar. Through sabotage and assassination with each House blaming the others, ROM swiftly increased the slide into lostech for many technologies taken for granted in the Star League era, all in the name of ensuring ComStar mission of being the sole protector of knowledge.
Like many parts of ComStar, ROM was splintered by the Reformation, however as the primary enforcers of the fanatical indoctrination of the old Order three fourths of the pre-schism ROM assets defected to the Word of Blake. This sheer numerical advantage gave them an edge in the brutal covert war with their secular brethren and against the Great Houses which allowed the Blakists to capture Terra and launch the Jihad.
The Jihad would wreak havoc as both sides of the sundered ROM, but again the secular branch would suffer the most damage. While ComStar would ultimately survive the Jihad, as part of the Republic Formation Treaty the secular Order was forbidden to operate its own armed forces or intelligence agency in return for its role in the new Republic of the Sphere. Though a number of ex-ROM members would attempt to retire, the bulk of the survivors of the disbanded agency would join the RAF's newly formed Department of Military Intelligence. 
 Known Operations
 Word of Blake
- March 14, 3074: ROM uncovers the presence of Hideoshi Yamika, chief researcher for Buda Weapons, on Luthien and leaks the information to the Kokuryu-kai, leading to the successful conclusion of the Battle of Skytower City.
 Command Structure
ROM reports directly to the Primus of ComStar or the Blakist Ruling Conclave via the Precentor ROM, who oversees the operations of the State Administrators, one for each Great House and major faction, who control and report on the day to day operations of ROM agents in their respective jurisdictions.
 Branches of ROM
Much like the Com Guards, the secular and Blakist ROM share a common origin. While the Blakist ROM has retained its traditional watchdog role and the branches associated with it, the secular ComStar had disbanded its versions and added a new branch not shared by their fanatical brethren focused on the Clan threat.
 Counterintelligence (Mu/Delta)
The foundation upon which ROM was built, counterintelligence is charged with locating and eliminating infiltrators from Successor States and, after the Schism, agents from the opposing faction. Under the reign of Raymond Karpov counterintelligence received almost carte blanche to employ whatever means it feels justified to ferret out enemy agents, both factions considering such strong arm brutality worth the price of maintaining their internal security, employing among the most fanatical members of ROM.
 Diplomatic Operations (Rho/Gamma)
Representing the Order's public face, the Diplomatic Operations Branch is devoted to public relations and selling the party line of its faction, pre-Reformation it was the Blessed Order's neutrality, after-wards the good intentions of each faction. Despite its soft image, due to its attendance at almost every diplomatic function across Inner Sphere, this branch is also highly adept at intelligence gathering.
 Covert Operations (Rho/Rho)
Originally intended to offer advance warning of Great House efforts to infiltrate the Order, under the aegis of Primus Karpov Covert Operations swelled into a brutal suppression of Great House technology. While the Blakist version maintains its role of assassination and misinformation against their so-called heretical brother and all major and minor factions in the Inner Sphere, the secular version has focused primarily against Free Worlds League and the Word of Blake.
 Information and Analysis (Mu/Mu)
With operatives stationed at every HPG facility, Information and Analysis screens all messages transferred on the HPG network for political, technical and military info of benefit to each respective faction, giving ROM an unrivaled advantage over every other intelligence agency across the Inner Sphere.
 Clan Liaison/Clan Overwatch (Rho/Chi)
A specialized variation of Covert Operations exclusive to the secular ComStar, this branch maintains and supports ROM's intelligence and sabotage operations in the Clan-occupied territories. Its original title found to be confusing, the branch was renamed after the Great Refusal with its focus redirected towards the Inner Sphere based Crusader Clans.
 Blake's Wrath/Light of Mankind (Delta/Epsilon)
Blake's Wrath and its renamed Blakist counterpart Light of Mankind represent each ROM's elite ground-based special forces. Made up of the Com Guards elite and trained in conventional and BattleMech combat, every member is also highly adept at covert operations.
 Valkyrie/Purifying Light (Delta/Xi)
ROM's elite aerospace special forces, Valkyrie and the Blakist Purifying Light is manned by the top three percent ranked kill ratio of Com Guard and Word of Blake Militia's AeroSpace Fighter pilots and receive the best anti-WarShip and WarShip defense training in the Inner Sphere.
 ComStar Security/Word of Blake Security (Mu/Iota)
This defensive branch is charged with protecting both each respective organizations high ranking officials and the HPG stations under their control.
 Internal Obedience (Rho/Omicron)
Internal Obedience was setup during the reign of Conrad Toyama to enforce the proper doctrinal mindset and devotion to the Blessed Order among its members. The secular ComStar has disbanded this branch, while the Word of Blake has maintained it, albeit under considerable strain due to the different views of its various sects.
 Spiritual Enlightenment (Mu/Psi)
This branch maintained the overall religious indoctrination preached by the old Order. Again, while the secular ComStar had no need for it, the Word of Blake ROM has maintained it, creating subdivisions catering to the codes of conduct and political views of each sect.
- ↑ Field Manual: 3085, p. 176 "Republic of the Sphere - The RAF - Administrative Divisions - Department of Military Intelligence"
- ↑ Jihad Turning Points: Luthien, pp. 10-11, "Light Machine"