Good Article
40px-Terminal.png This article, COSSACK-class Mjolnir Powered Assault Armor, was written by EvenManatee887. Please do not edit this fiction without the writer's permission.
COSSACK-class Mjolnir
Production History
Designed by

Imbrium Machine Complex






Imbrium Machine Complex


221.7 kg (488.7 Lbs)

  • Compressed Fullerene Buckyball Carbon Nanotubules
  • Hyperdiamond Fibers
  • UST-47B (Coyote-D7) Advanced Sensor-Scanner Cluster
  • 2U-34 Universal Uplink and Intrusion Unit
  • 7P-LCF Energy Shield Actuator Plug Components
  • X880-Boulder Emission Shroud (IMC-Spec)
  • Bravado-120-B3 Fitted Reactor Pack Stabilizer
  • P-9 Open-Line Channel Modifier
  • IR-13 Inertial Dampeners
  • 'Chronicon' Information Management A.I
  • HTI-3 Datalink
  • HDP-57 Micro Projection System
  • MU-17 External Hardpoints


"The Cossacks acted as guardians for people living on the fringes of their nation, living, fighting and surviving in the wild. Today, we pick up that mantle."
―IMC spokesperson, when revealing the COSSACK-class Mjolnir.

The COSSACK-class Mjolnir is a GEN2 Mjolnir suit derived from the now-discontinued RANGER-class Mjolnir. The suit shares many similarities with RANGER, including using the same basic chassis and body armor, with the main differences being in their role, features and capabilities of the suit.

During the designing of the RANGER-class Mjolnir, Imbrium Machine Complex (IMC) submitted two designs for the UNSC Ordnance Commission to review. One focused on simpler forms of combat versatility, survivability and toughness, which would come to be known as RANGER. The other, meanwhile, was a far more technologically-aided and arguably more versatile suit, but as a result of this it was far more sensitive to damage; this would come to be known as the COSSACK-class Mjolnir.

Despite its rejection by the Ordnance Commission, the Experimental Armor Division of IMC would keep prototypes of the armor and consistently work on it through the Post-War years. The suit began to enter active service as the decreasing production and ongoing maintenance issues of the RANGER-class Mjolnir lead to a demand for a new suit. As of October 2558 and the cessation of production of RANGER-class Mjolnir, COSSACK has only been issued to 5 Spartans.


The origins of the COSSACK-class Mjolnir preceeds the introduction of the Mjolnir GEN2 and lies in the GEN1 Mark IV armor, namely in the SCOUT and RECON-class Mjolnir. The introduction of these armor, and associated software, allowed Spartans in the field to freely operate deep behind enemy lines for extended periods of time, often with impunity thanks to their limited stealth capabilities. It was this operational flexibility and independence in the field that saw a greater focus into armors of this type, namely as the SCOUT focused on individual target tracking and sniper operations while RECON focused on reconnaissance and intel gathering. As a result of this gap in capability, several pre-existing suits such as SCOUT and RECON-class Mjolnir armors saw substantial expansions of their capabilities when transitioning to the Mark V [B] platform.

It was with the introduction of the Mark V [B] that Materials Group began to outsource armor design to select companies, one such company was IMC, which would be tasked with assisting in the development of a dedicated suit of armor for independent, long term operations deep behind enemy lines. The lead designer supplied by IMC was one Dr. Wyatt Evermann, a leading figure in the development of exceptionally rugged yet still capable hardware. The main focus of Dr. Evermanns team was to develop a suit of armor which was rugged enough to serve for a minimum of 8 months in exceptionally rough terrain while maintaining sufficient systems and tools to allow the operator to plan, co-ordinate and carry out operations without support from other units. Initial concepts of the design seemed to balance the amount of tech in the suit fairly well to the ruggedness of it, but as the team progressed and the first prototypes began to roll out, there was a notable increase in conflict between Materials Group and Dr. Evermanns team.

Dr. Evermann sought to include more advanced components to allow the suit to operate behind enemy lines, theoretically, for as long as was needed. Such components included a series of micro-drones and even a built-in suit maintenance kit, which allowed the operator to conduct limited repairs to the suit and even take it off, all without the need of specialists or specialized equipment. The major flaw seen by Materials Group with these numerous advanced technologies was that they made they suit far more reliant on them for survival, as opposed to the innate ruggedness of components and the armor itself. So after much deliberation with Dr. Evermann and his team, the decision was made to create a second batch of prototypes which would follow Evermann's more advanced design while the first batch would retain Materials Groups original idea for an innately rugged suit. These two suits would become known as COSSACK and RANGER-class Mjolnir respectively.

Development History

Between 2556 and 2558, the COSSACK-class Mjolnir saw many iterations and features both in its design and features. Such examples included a variant with ad hoc compatibility and a slew of modular armor panels to allow the suit to be adjusted both before and even during a mission to suit the situation. This was later abandoned, as the running cost of the suit were estimated to be too high. Another variant was a stealth focused variant, which derived signature masking systems and attachments from the PATHFINDER and RECON-class Mjolnir. However, these were also rejected as their current form offered limited in the way of in field adaptation.

In 2557, pre-production models of COSSACK-class Mjolnir were deployed on-board the UNSC Infinity and saw action during the Battle of Requiem, where they acted as forward recon and scouts to establish a perimeter around the Infinity. They were also deployed in a limited capacity to respond to ever-increasing Kig-Yar pirate raids. These provided vital info which lead to advancements in the inertial dampeners and maneuvering thrusters.

By January 2558, the suit had reached its final production model. The suit still retained the body armor and design from the RANGER-class Mjolnir, but thanks to advancements in software and component miniaturization, it also featured far more in the way of features. The suit formally entered service in April 2558, after trials in Bosque de Negro and the Anakara Resiliency Chamber.

Operational History

Design Specifications

COSSACK-class Mjolnir shares many similarities with its sister suit, the RANGER-class Mjolnir. Most notably the two share externally identical body armor, with the only substantial differences being underneath the armor. However, the helmet used in COSSACK is a far cry from the one used in RANGER, foregoing the larger and more blocky helmet and the difficult-to-maintain bifocal visor. In their place, the new helmet features a far more rounded design around the top of the head, with a more angular design present around the jaw and eye line. Notable visual cues would be the V-shaped visor, which allows a better field of view for the operator while keeping the visor low profile enough to not easily break in harsh conditions or combat. The most striking difference between the two helmets would be the large bulbous protrusion on the forehead of the COSSACK-class Mjolnir, which houses the unified UST-47B (Coyote-D7) Sensor-Scanner Cluster. However, during the suit's development, there was much controversy surrounding the helmet due to the striking resemblance to the FENRIR-class Mjolnir. IMC was accused of industrial espionage, however, due to the lack of evidence, the case was closed soon after it was opened.

The body armor has also seen a degree of reworking, as with Lethbridge Industrial acquiring damaged or disposed RANGER-class Mjolnir, there have been security concerns regarding the COSSACK-class Mjolnir. In response, a new and more advanced, albeit easier-to-maintain, software architecture was developed for the COSSACK, which bears little similarity to its previous iteration. The main reason for the stark differences between the two is because of the amount of technology that the software needs to support compared to the previous suit. However, given the way the suit operates, it also provides added protection to the suit systems.

Role and Usage

"Be it shifting sands, freezing blizzards or the depths of swamps, the inexorable COSSACK-class Mjolnir trudges on 'till the mission is complete."
―Promotional tag for the COSSACK-class Mjolnir

When COSSACK-class Mjolnir first came into service, a wide variety of of suits already in service, such as RECON, SCOUT, TRACKER and PATHFINDER, had considerable overlap with it. The decision was made to gear this suit towards two particular fields, while emphasizing the RANGER-class Mjolnir's hallmarks of Versatility, Survivability and Operational Independence.

The first of these fields are what are called 'Ranger' Operations. 'Ranger' Operations are the suit's true purpose, as no other suits can clearly fill the role or are as well-suited for it. 'Ranger' Operations outline that a single operator or groups of operators are deployed to hostile-held or occupied areas, with the aim to gather intelligence, conduct guerrilla warfare, organize rebellions or discontent on the planet they are deployed to, and conducting counterinsurgency/anti-criminal operations.

The suit fills this role with peak performance, as it is able to silently be inserted and operated with little-to-no evidence of the operator being left behind, due to the use of inertial dampeners. These remove the need for insertion vehicles, and radar absorbent coating and emissions baffling to mask the IR and emissions signature of the suit after it has landed. Due to 'Ranger' Operations often meaning the operator(s) will be cut off from large scale outside support, the suit is able to link with, or break into, friendly or non-friendly systems respectively without any intermediary device.

The added presence of information-gathering systems also allow the operator to organize and plan around hostile force. The suit can also allow the operator to send information back to command elements via friendly satellites such as STARS. This is not very common outside of specific intel gathering missions, as doing so risks compromising the operators location and impeding further operations. To a lesser degree, the suit can also be used in reconnaissance missions. However, this is uncommon as there are other suits better suited to the task. Reconnaissance meaning that the suit can be deployed by itself or in a group, either behind enemy lines or in forward positions to provide intel on enemy movements, troop concentrations and possible terrain obstructions in support of a larger force or prior to an attack.

Armor Components


The techsuit is largely the same as the standard GEN2 Mjolnir Techsuit, composed of a Titanium Nanocomposite Bodysuit with an Inner Skinsuit. However, the version used in COSSACK-class Mjolnir is somewhat different, as it has thicker and more resistant section at all major joints such as the elbows and knees, as well as around the abdomen, chest and around the collar. The bodysuit in these areas is far more strain-resistant, due to the use of compressed carbon lattices. These are then drawn into strands to make a flexible but strong padding, makes it capable of taking far more punishment from outside sources, both by combat and environmental hazards.

Armor Composition

Like most other Mjolnir GEN2 suits, the COSSACK-class Mjolnir features an outer Titanium Shell which makes up the bulk of the armor on the suit. However, during the development of COSSACK, several new and supplementary forms of armor were developed. Namely, the COSSACK-class Mjolnir features two layers of new, lightweight and high strength materials, which are known barely known outside of IMCs Experimental Armor Division.

Full 3

A model of C60 Fullerene displaying the surface level hexagon structure

The outer layer of the armor is composed of C60 Fullerene molecules, which are then compressed into a double layered structure from one of the surface hexagon structures. These are then bound together into a much larger and flatter structure. These are then used to form the Carbon Nanotubules, and effectively have twice the layering of normal carbon nanotubes. This results in an incredibly strong and light layer, which in testing it has shown impressive heat and electrical conductivity.

While in most cases this would require a redesign due to the nature of plasma weapons, IMC decided to work around the issue. To rectify the issue a lining was developed which would essentially coat the inner and outer faces of the carbon nanotubes in a layer of thin, albeit dense, ceramics. This would insulate each layer of the armor against plasma impacting the outermost layer.

The inner layer is much the same as the outer layer, however it features one key difference. Hyperdiamond Fibers are laced through the Carbon Nanotubes which further bolsters the conductive qualities of the layer but also allows for more layers of ceramic to be inserted into the nanotubes. Similarly each layer is combined with a thin layer of ceramic insulation to decrease the chance of any electrical current or heat damaging the suit's internal systems.

UST-47B (Coyote-D7) Advanced Sensor-Scanner Cluster

"COSSACK-class Mjolnir allows the Spartan using it to operate, map and clear out the combat zone at their discretion."
―Armory Description for COSSACK-class Mjolnir Helmet.
HM 1

Mounted on the forehead of the helmet in a large, bulbous, armored protrusion is the UST-47B, otherwise known as the Coyote-D7, Advanced Sensor-Scanner Cluster. The cluster is constantly working, either passively or actively, and features redundant environmental scanners whose sensor fidelity and high-bandwidth storage capacity make it ideal for detailed environment scans, intelligence analysis and scene reconstructions.

The scanners take highly detailed, broad spectrum scans of the area around the operator, out to a range of 45 meters in any direction. This information is then processed alongside target information obtained from the sensors to create a highly detailed 3D Holo-Map in place of the standard mini-map by use of an advanced 3D Cartography Software. This results in detailed terrain and target orientations, such as elevation changes, obstacles and orientation of targets. The cluster can also act in conjunction with outside information systems the suit is uplinked to, such as satellites, cameras or sensors systems, to enhance the range and detail of the map. However, the system is not solely used for the map generation software, and can act as a long range reconnaissance unit to scan, outline and mark targets out at long-range.

2U-34 Universal Uplink and Intrusion Unit

The 2U-34 Universal Uplink and Intrusion Unit is an, encrypted, high sensitivity, broad spectrum, low-probability-of-intercept uplink unit. It is used to remotely connect to any standard UNSC terminal or device, such as data-pads, satellites, terminals and data centers over extreme distances. The advantage of such a system is its lack of reliance on any intermediary devices, such as a signal booster or direct connection which allows the operator to remain on the move. It also has the added function of being able to remotely hack into such systems, both human and Covenant. The intrusion system works on its own channel so as to prevent the suits main systems being compromised in the event of a cyberattack.

The information obtained by the suits sensors and scanners, such as the terrain and target info, can also be routed through the 2U-34 and beamed to any nearby friendly device. In particular, the suit is rated to connect via secure and encrypted channels to STARS satellites to export any information. However, if the suit is unable to do so it can offload the data during mission debriefings. With the aid of a dedicated 'Smart' or 'Dumb' A.I, the capabilities of the the unit can be furthered to allow for breaking into encrypted hostile battlenets or other secure systems. Similarly it would also allow data to be received and sent far faster due to the added processing power of an A.I.

SPU-457 Dispersal Field Generator

The SPU-457 Dispersal Field Generator is the main shield generator of the COSSACK-class Mjolnir. It was developed from the same shield generator that was utilized by the RANGER-class Mjolnir and as a result it features a similar set of capabilities. Namely it has an above average radiation shield strength which allows the suit to operate for prolonged periods of time in extreme heat or cold and in certain high radioactivity zones. However the latter is avoided as the suit is not equipped with sufficient filtering mechanisms to spend prolonged time in these areas. Being derived from RANGER-class Mjolnir it features compatibility with the 7P-LCF Energy Shield Actuator Plug Components which are also carried over from the RANGER-class Mjolnir. These allow the operator of the suit to adjust the overall strength of the suits energy shields to suit the needs of the mission or if they need to conserve power.

RFX-136 Compact Fusion Reactor

"COSSACK-class Mjolnir has regularly shown its capability to operate without support or detection for months on end and in the harshest conditions."
―Armory Description for COSSACK-class Mjolnir Armor.

The RFX-136 Compact Fusion Reactor is the powerplant of the COSSACK-class Mjolnir and was newly developed by IMC specifically for it, featuring a number of improvements and components to achieve optimal performance in the field. One such feature is the P-9 Open-Line Channel Modifier built into the reactor pack and allows for far greater control over the output of the reactor, so it can be adjusted in the field and without specialized equipment to conserve power.

Similarly there is the Regal-160-B3 which is a fitted reactor pack stabilizer, similar to the Bravado-120-B4 utilized on the RECON-class Mjolnir.The main function of the Regal-160-B3 is that it allows the reactor pack to suffer a greater amount of damage before destabilizing while being fairly low profile. Another advantage is that is allows the reactor to be more efficient, this being a result of the more stable casing. While similar to the X900-Boulder Emission Shroud used on the RECON-class Mjolnir, the Z780-Berg Emission Shroud is considerably smaller and more efficient, as well as that it is able to operate far better in extreme heat or cold, albeit at the cost of its overall performance.

IR-13 Inertial Dampeners

The IR-13 Inertial Dampeners are located throughout the suit and allow the operator to conduct High Altitude High Opening (HAHO) and High Altitude Low Opening (HALO) Jumps, and allow for insertion into the combat zone without a vehicle and with a minimal radar signature and sound. It also makes insertion of operations into hostile territory much less risky for both the operator and any associated vehicles.

'Chronicon' Information Management A.I

The 'Chronicon' Information Management A.I is a purpose built Armor A.I made specifically for the COSSACK-class Mjolnir. It was designed to handle the sheer amount of data the suit processes through the UST-47B and when uplinking to Satellites which would possibly overwhelm and interfere with the suits normal functions. Being a suit A.I, the Chronicon is fully capable of working alongside or supplanting an on-board 'Dumb' or 'Smart' A.I. This has shown to be incredibly effective with test modules being able to run both the UST-47B and 2U-34 at maximum performance with seemingly no issues. IMC's systems management A.I 'Louis', had reported a friendly behavior of the A.I but also reported instances of the A.I cataloging segments of its interactions with Louis, these were subsequently wiped.

HTI-3 Datalink

The HTI-3 Datalink is a high speed, high capacity datalink used in the armor to more easily manage the copious amounts of information acquired by both the normal sensors and scanner but also the far more detailed information supplied by the UST-47B. They also greatly aid in sorting and compartmentalizing outside data such as that received when uplinked to a data center or satellite.

HDP-57 Micro Projection System

HM 1

The map details areas with hostiles in an orange hue if there is insufficient target info.

The HDP-57 Micro Projection System is a forearm mounted holographic interface which can be used to project holograms of info being received by the suit such as holo-messages, holo-maps or target dossiers. It is capable of projecting large detailed maps compiled by the 3D Cartography Software used to produce the 3D minimap. As an added feature the map will localize to the operator and have them be standing on their position on the map. The system can also be used to reconstruct scenes or locations the suit has already been through in high fidelity.

MU-17 External Hardpoints

The MU-17 External Hardpoints are hardpoints mounted on the forearms, sides of the thighs, sides of the calves, hips and on the small armored panel on the posterior of the armor. These harpoints can be used to carry ammo pouches, equipment or other ad hoc pieces such as signature breaking panels to aid the armor in staying hidden on hostile sensors.

Notable Users


Following Jamie-B295's return from Tosion she displayed a particularly close relationship with the Rangers she had been deployed with for over 9 years. As a result she had made a formal request to be permanently assigned to the unit which was acquiesced to by the head of Spartan Branch, Musa Ghanem, as a test for the viability of permanent joint branch teams.

As a result of her posting she was one of the first recipients of the COSSACK-class Mjolnir and has since consistently shown that the armor can take the strains and rigors of long term, unsupported missions in enemy territory. This was made explicitly clear when she, alongside several other Rangers, deployed via HALO jump and wiped out an entire Kig-Yar pirate camp within the span of 4 hours and marched back to friendly territory without difficulty.

Fireteam Bedouin

Fireteam Bedouin was the first full team of Spartans equipped with COSSACK-class Mjolnir. The team operated in several counter-insurgency operations in the Outer Colonies, specifically targeting Insurrectionist leaders and infrastructure.

Community content is available under CC-BY-SA unless otherwise noted.