Production information
Manufacturer Ceres Metal Industries[1]

Detroit Consolidated MechWorks[1]

Kong Interstellar Corporation[2]

Krupp Armament Works

Luthien Armor Works

Ostmann Industries

Ronin Incorporated[3]

Vandenberg Mechanized Industries[1]

Production Year 2511[4][5]
Model OSR-2C
Class Heavy
Cost 5,025,600 C-bills
Technical specifications
'Mech type Inner Sphere BattleMech
Mass 60 tons
Chassis OST-II
Armor Riese-475
Engine Vlar 300
Communications System Ostmann-L
Targeting Tracking System Ferdinand-a
Heat Sinks 15 single
Speed 86.4 km/h
BV (1.0) 951[6]
BV (2.0) 1,228[4][7]


The Ostroc is a heavy 'Mech, weighing in at the lower end of its weight class, originally designed to act as an urban combatant during the Age of War. The best-known of Ostmann Industries' Ost class of 'Mechs, the Ostroc debuted in 2511 and proved so successful in this role production continued for approximately 200 years. Its unique walker/pod profile, later seen in the Stalker and Marauder, combined with a low silhouette similar to the UrbanMech makes the Ostroc difficult to spot in an urban environment. Fast for its size, well-armored and boasting good medium- and short-range firepower, the Ostroc was also capable when fighting outside a cityscape, particularly as a heavy scout/raider.[4][8]

While a quality 'Mech, the low production capacity of Ostmann Industries made the Ostroc a rarity; indeed the company licensed their other "Ost" 'Mechs out to Kong Interstellar just to maintain their rate of production, and the majority of those produced were assigned garrison duties within the Terran Hegemony. Still, the 'Mech saw action in every major conflict of the Star League, especially towards the end in the civil war and subsequent First Succession War. The destruction of Ostmann Industries meant an end to any new Ostrocs, although all sides of the Succession Wars continued to field these 'Mechs in combat, particularly the Draconis Combine. It was because of the small number and wide dispersal of surviving Ostrocs that the design was largely passed over while others were being updated after the Helm Memory Core discovery.[4][8][9]

A major revitalization of the design took place within the Capellan Confederation after the Clan Invasion. Having largely rebuilt their forces after the previous decades' setbacks, the Strategios wanted to update the ancient 'Mech, but rather than reverse engineering the original they ordered all Capellan 'Mech manufacturers to submit bids for a replacement. Ceres Metals was the only one to send in a proposal which matched exactly what they wanted and won the contract, completing the first production run in January 3067. Versions of these new Ostrocs also started showing up in the Taurian Concordat and Circinus Federation, a result of espionage according to Capellan charges.[10]

Weapons and Equipment[edit]

The Ostroc carries as its primary weapons two Fuersturm-C large lasers in the left and right torsos. These give the Ostroc good medium to long range damage capabilities. The Ostroc's secondary weapons are two Fuersturm-b medium lasers also mounted in the side torsos and a Totschlagen SRM-4 launcher in the right torso for close-range combat, with one ton of reloads carried in the center torso. While the Ostroc's laser-heavy weapons payload allows it to operate well as a guerrilla fighter since it has limited dependency on supply lines, its short arms are a handicap in close combat, and the shocks of hand-to-hand fighting can easily damage the Fuersturm systems. The nineteen-ton Vlar 300 fusion engine propels the Ostroc to a cruising speed of 86.4 km/h, fast for its size, while fifteen heat sinks provide adequate heat management. Although nine tons of armor provide good protection for the 'Mech, very little is used to protect the arms, meaning the loss of one or both in battle is likely.[4][8][11]


Ostroc Mk II redirects here.
  • OSR-2D 
    Upgraded with Star League technology, the 2D variant of the Ostroc extends the 'Mech's maximum range by replacing the large lasers with two ER large lasers. The 2D retains the medium lasers and SRM-4 of the 2C model. To handle the heat burden it is also equipped with double heat sinks. Being a relatively rare design, the Ostroc had no official field refit kit but the 2D variant was a common upgrade in 3050 if the parts could be obtained.[9][15] BV (1.0) = 942;[6] BV (2.0) = 1,396[16]
  • OSR-2L 
    The 2L variant of the Ostroc introduced in 2884 is modified for long range combat. The SRM-4 launcher has been replaced with an LRM-5 launcher, increasing the 'Mech's long-range damage capabilities slightly by sacrificing some of its close range firepower.[17] BV (1.0) = 970;[6] BV (2.0) = 1,233[18]
  • OSR-2M 
    An experimental model produced by Kong Interstellar for the Free Worlds League in 2793, the 2M variant of the Ostroc focuses on the 'Mech's maneuverability. Five jump jets, two in each leg and one in the rear torso, have been added to the design, giving it a maximum jumping distance of one hundred and fifty meters. In order to make this change, the medium lasers and the SRM-4 launcher were removed. Relatively few of these were built between the League's annexation of Connaught and the factory's destruction.[4][19] BV (1.0) = 1,036;[20] BV (2.0) = 1,239[21]
  • OSR-3C 
    The 3C variant looks to improve the long-range direct firepower of the Ostroc. Introduced in 2876, the two medium lasers and the SRM-4 have been removed in order to add a third large laser mounted in the right torso.[22] BV (1.0) = 976;[6] BV (2.0) = 1,288[23]
  • OSR-3M 
    The -3M is a modest upgrade, a bracket fighter created with Regulan self-sufficiency in mind. Built on Wallis by Ronin Incorporated, this variant draws heavily on locally sourced Ostwar components, a bevy of tried and true extended-range lasers provide the bulk of its firepower, managed via double heat sinks. A supercharger is the greatest update, giving it a burst of speed when the occasion demands.[24] Its armor is upgraded with light ferro-fibrous armor, while it is armed with an ER large lasers and two ER medium lasers in each torso side, with the additional upgrade of the SRM-4 to a Streak SRM-4. BV (2.0) = 1594[25]
  • OSR-4C 
    A Periphery variant of the Ostroc produced by Vandenberg Mechanized Industries on New Vandenberg and also found in the Circinus Federation, the 4C is strikingly similar to the Capellans' 4L variant. Its armor has been upgraded with nine tons of ferro-fibrous armor, giving it more protection than previous models. Additionally, the SRM-4 launcher has been removed in favor of two rocket launcher 10s and two rocket launcher 15s, giving the 'Mech an incredible one-shot damage capability.[1][26] BV (1.0) = 1,089;[27] BV (2.0) = 1,325[28]
  • OSR-4K 
    This version was introduced by House Kurita in 3077. A heavy-duty gyro allows it to stay in the fight longer, making good use of twin snub-nose PPCs and ER medium lasers. Though it's slightly slower than the standard Ostroc, jump jets allow it to maneuver around the battlefield, striking where it will inflict the most damage. After the Jihad ended, this model went into factory production.[29] BV (2.0) = 1,490[30]
  • OSR-4L 
    A complete redesign of the Ostroc, the 4L carries the best technology the Capellan Confederation has to offer in 3067. It uses a Ceresplex Ostroc Lite endo steel chassis to carry two Martell ER large lasers and two Ceres Arms ER medium lasers split between the side torsos. Five HildCo 13 jump jets split between the side and center torsos gives it a jumping distance of 180 meters. Finally, the 4L Ostroc has a Guardian ECM suite for electronic warfare use and to work with ten and a half tons of stealth armor which makes it extremely difficult to hit. While it was originally supposed to use only standard armor, the addition of stealth capabilities makes this variant well suited for operating as a member of Capellan Shadow Lances. For electronics the Ostroc carries the Ceres Metals Model 686 and Ceres Bullseye systems.[10][31] BV (1.0) = 1,431;[32] BV (2.0) = 1,832[33]
  • OSR-5C 
    Based on the 4C, this Taurian version introduced in 3082 uses an XL Engine, endo steel chassis, and five jump jets. The armament has been replaced with a heavy PPC and light PPC.[34] BV (2.0) = 1,788[35]
  • OSR-6R 
    Kong Interstellar, a licensee of Ostmann, survived the Succession Wars, and in 3139 returned to its roots and resumed construction with the help of Clan Sea Fox. This new model opted to upgrade the design to include reflective armor, an endo-composite skeleton, a larger 360 XL engine that can reach 97.2 km/h, CASE II and Clan-grade lasers.[24] Its weapons include two Clan-Spec ER large lasers, two ER medium lasers, and an Inner Sphere Streak SRM-4. BV (2.0) = 2,095[25]
  • OSR-9C Ostroc Mk II
    This FrankenMech variant of the Ostroc, built with parts from the Ostwar,[24] swaps the SRM-4 for one SRM-2 launcher in each arm, with one ton of ammunition in the center torso. Half a ton of armor was added to the front torso and legs (adding one point to each leg and side torso, and four to center torso), and four more heat sinks were installed along with three jump jets for a jump capacity of 90 meters. To make room for these components, the engine had to be changed to a Pitban 240, reducing the top speed to 64.8 km/h. (See also Notes below). BV (2.0) = 1,230[38]
  • Ostwar Hybrid 
    Spare parts for the Ostroc were hard to come by in the lostech days of the Succession Wars era, which resulted in many Ostrocs being refitted with parts from an earlier design by the same manufacturer, the Ostwar. Ostrocs mounting the Ostwar's arm/hand assembly with paddle-like SRM-4 launchers became such a common sight that many falsely believed this to be the original configuration of the Ostroc (see Notes below).

Custom Variants[edit]

  • OSR-2C Ostroc Michi 
    Piloted by Michi Noketsuna (see Notable Pilots below) in the fighting on Misery against Wolf's Dragoons in 3028, this customized Ostroc had a top speed of 64 km/h. The reduced engine size allowed the Ostroc Michi to jump 120 meters and replace the SRM-4 with an SRM-6 launcher. BV (2.0) = 1,321[39]

Design Quirks[edit]

The Ostroc has the following Design Quirk:[40]

Related BattleMechs[edit]

  • Ostsol - The Ostsol was designed and introduced near the end of the Ostroc's production. The Ostsol was designed to be independent of ammunition, allowing the Ostsol to be a much better deep raider than its primogenitor.
  • Ostwar - The Ostroc was designed as an upgraded replacement to the Ostwar BattleMech.

Notable Pilots[edit]

  • David Levine was a well-known MechWarrior-Technician in the 22nd Avalon Hussars, who enhanced his blue-and-grey Ostroc's electronics. His modifications (and success as a raider) drew the attention of Hanse Davion, who held a personal conference with Levine around 3025.[8] Kurita-aligned bounty hunters, however, accidentally killed him and destroyed his 'Mech in a failed kidnapping before the NAIS could attempt to duplicate his innovations.[4]


  • The original art going with the Ostroc when it was first published in Technical Readout: 3025 and CityTech pictured the 'Mech with two flat, paddle-like devices with what looked like four missile ports each for "hands" on both arms instead of the torso-mounted launcher. Although associated with the 'Mech, this image was later clarified to be a common but nevertheless nonstandard variant employing spare parts that were originally meant for another 'Mech, the rare Ostwar (which does feature SRM-4 launchers instead of hands); the Ostwar was a precursor of the Ostroc and many of their components were interchangeable. (See Ostwar Hybrid variant above.)
    It should be noted that the standard Ostroc mounts its single SRM-4 launcher in the right torso, and has two fully modeled hands. The launcher of this standard version sits upright in the right torso section. This standard configuration with hands and a launcher in the right torso was used for the miniature (see left), depicted in Technical Readout: 3050 and also used in various artwork such as the McCarron's Armored Cavalry scenario pack which depicts three Ostrocs with hands and a shoulder-mounted SRM launcher on the cover.
  • The Ostroc Mk II as canonized in the 2021 Recognition Guide: ilClan, vol. 21 actually stems from an obscure apocryphal product published 35 years prior that first introduced the 'Mech, the 1986 TCI Set 7: Marauder and Ostroc Mk II model kit set from Twentieth Century Imports (TCI). It contained game stat sheets for the classic MAD-3R Marauder and the OSR-9C Ostroc Mk II. Of the design's three jump jets, one sits in the center torso while the other two are reportedly mounted in the arms. This fits with the picture and was legal under the earliest design rules from the original Battledroids game, but has been illegal since BattleTech 2nd Edition (BattleTech rules allow jump jets only in the legs and torso sections). Other than that, the design is legal under current construction rules, including the correct mass to the jump jets (1 ton each). The additional armor was allocated to the front torso (4 points to center torso, 1 to each side torso) and legs (1 point each).In the scenario accompanying the model kit and stat sheet, a House Davion MechWarrior recounts how he encountered an Ostroc that "had been obviously modified" in the defense of Brittany III against a Kurita invasion. The name of the Ostroc Mk II's pilot is given as DeMici.



  1. 1.0 1.1 1.2 1.3 Technical Readout: Jihad, pp. 132–133: "OSR-4L Ostroc"
  2. Recognition Guide: ilClan, vol. 21, p. 7
  3. Recognition Guide: ilClan, vol. 21, p. 7
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Technical Readout: 3039, p. 291
  5. Era Digest: Age of War, p. 11
  6. 6.0 6.1 6.2 6.3 Combat Operations, p. 121
  7. Record Sheets: 3039 Unabridged, p. 466
  8. 8.0 8.1 8.2 8.3 Technical Readout: 3025, p. 76
  9. 9.0 9.1 Technical Readout: 3050, p. 122
  10. 10.0 10.1 Technical Readout: Project Phoenix, p. 34
  11. Record Sheets: Phoenix Upgrade, p. 118
  12. Technical Readout: 3075, p. 169
  13. Record Sheets: 3075 Unabridged, p. 170
  14. Record Sheets: 3075 Unabridged - Age of War, p. 24
  15. Record Sheets: Phoenix Upgrade, p. 119: "Note that the record sheet erroneously supplies this design with single heat sinks. They are, in fact, double heat sinks." [1] (dead link)
  16. Record Sheets: 3085 Unabridged — Project Phoenix, p. 97
  17. Record Sheets: Phoenix Upgrade, p. 120
  18. Record Sheets: 3039 Unabridged, p. 467
  19. Record Sheets: Phoenix Upgrade, p. 121
  20. Combat Operations, p. 130
  21. Record Sheets: 3039 Unabridged, p. 468
  22. Record Sheets: Phoenix Upgrade, p. 122
  23. Record Sheets: 3039 Unabridged, p. 469
  24. 24.0 24.1 24.2 IlClan Recognition Guide, vol. 21, p. 6
  25. 25.0 25.1 IlClan Recognition Guide 21, p. 7
  26. Record Sheets: Phoenix Upgrade, p. 123
  27. Combat Operations, p. 138
  28. Record Sheets: 3085 Unabridged — Project Phoenix, p. 98
  29. Technical Readout: 3085, p. 246
  30. Record Sheets: 3085 Unabridged — Project Phoenix, p. 99
  31. Record Sheets: Phoenix Upgrade, p. 124
  32. Combat Operations, p. 122
  33. Record Sheets: 3085 Unabridged — Project Phoenix, p. 100
  34. Technical Readout: 3085, p. 246
  35. Record Sheets: 3085 Unabridged — Project Phoenix, p. 101
  36. Record Sheets: Phoenix Upgrade, p. 125: "Blakist In-Fighter"
  37. Technical Readout: 3085, p. 247
  38. IlClan Recognition Guide 21, p. 24
  39. Historical Turning Points: Misery, p. 17
  40. BattleMech Manual, p. 93: Design Quirk Table - Ostroc Entry