Timeline Discussion: The Grineer-Corpus War and Project Tethra

The Grineer are a massive empire that has, for much of the modern history of the Origin System, been in bitter competition with the only other faction that can rival it in terms of territory, military strength, and economic output: the Corpus. This discussion post details the conflict between the two, as well as expounding on a particular military initiative that was borne from this war and was ultimately turned against the Tenno: the Balor Fomorians.


The March to War

The natures of the Grineer and the Corpus prior to the awakening of the Tenno are somewhat murky, but are presumed to be similar to what they are now: vast territorial powers, with large space navies and multiple planetary bases (the histories of the Grineer and Corpus will be covered in more detail in future discussions). By the time the first Tenno woke from cryosleep, both factions had control over large sections of the Origin System, and were intent on spreading their influence further. The Corpus controlled the Solar Rail network1, as well as access to resources2, but were more than willing to sell both of these privileges to the Grineer. The Grineer, for their part, were not afraid to use their military might to threaten the Corpus if negotiations did not go their way.

The Fusion Moa Exterminate Weekend and the Informant Event, two of the first Operations undertaken by the Tenno, saw the Corpus and Grineer, respectively, develop new technology in an attempt to extend their control over the System (both events were thwarted by the Tenno). Each event was fairly self-contained, but they both demonstrated the desire of each faction to spread their influence and control throughout the System.

Operation: Sling-Stone was the first noted conflict between the two great powers. Prior to the event, the Corpus had been stockpiling resources, allowing them to restrict supply and artificially inflate prices. The Grineer Queens eventually deduced this fact and demanded contract renegotiation, threatening retaliation via a secret new fleet of Fomorian ships. The Corpus Board of Directors did not believe the Fomorians existed, and raised material prices further. The Grineer promptly activated their fleet, sending a Fomorian to each planet in the System with orders to destroy the Corpus resource stockpiles. The Lotus reasoned that Grineer military power could not be allowed to grow so drastically. Additionally, destruction of the stockpiles would detrimentally affect the Tenno’s own ability to obtain resources. She therefore instructed the Tenno to infiltrate and sabotage the Fomorians as they appeared, using chemicals harvested from Infested tissue to corrupt and destabilise the Fomorian reactors. Over time, repeated acts of sabotage by the Tenno overwhelmed the Grineer’s ability to repair the damage, and each Fomorian reactor eventually destabilised, destroying the ship. All Fomorian ships were destroyed before they were able to target the resource stockpiles; thus, the Corpus are not known to have suffered any losses in this conflict. Alad V, who was administering the situation on behalf of the Board, compensated the Tenno for their service with ammo mutation mods – a miniscule cost in lieu of the potential damages. Following the destruction of their great fleet, the Grineer once again turned to diplomacy to settle the resource conflict, though Alad V suspected that the Grineer had held some Fomorian ships in reserve, and sent scouts to probe the matter.

In the aftermath of Operation: Sling-Stone, the Grineer and Corpus resumed their previous dealings with each other. This was revealed when the Lotus uncovered evidence of new Grineer settlements that the Corpus were keeping secret from the Tenno. Presumably, the Corpus’ help was necessary because they still maintained control of the Solar Rail network at this time. It is unknown why the Grineer were so intent on keeping the settlements secret, as no strategic targets are known to have been located there, but they paid the Corpus a high price for the service, and so the Corpus were anxious to preserve their contract. Once the Corpus learned that the Tenno were aware of the project, they gathered their Scouts in possession of the navigational data and hid them on Corpus ships in the Void. Undeterred, the Tenno launched Operation: Arid Fear and pursued the Scouts into the Void and captured them, bringing the data to the Lotus to assemble. Eventually, the Tenno were able to uncover the Grineer settlements on the planet Mars3. The Grineer captain Vor moved to reinforce the settlements in preparation for Tenno incursion, transmitting to the Queens his disappointment in the Corpus for their underestimation of the Tenno, and his own musings on the Tenno’s nature.

Finally, during the Gradivus Dilemma, the tensions between the two superpowers erupted into a direct conflict. Alad V’s scouts (possibly the same dispatched to Pluto in the wake of Operation: Sling-Stone) uncovered a large cache of intact Tenno cryopods on Sedna. By this time, Alad’s Zanuka Project was in development, and he needed additional warframes to improve his proxies. Alad saw the Project as a critical strategy to liberate the Corpus from the Grineer’s threatening military might. General Sargas Ruk of the Grineer intercepted Alad’s message to the Board, and demanded Alad turn over the Tenno, according to their contract. When Alad V refused to concede, Sargas Ruk invaded Corpus positions on Mars. Both sides recruited the Tenno to fight for them. The Lotus, knowing that the Tenno community held differing opinions, refrained from issuing orders, allowing individual Tenno agents to obey their conscience and choose a side. In the end, Sargas and his Grineer won the battle for Mars, exhausting Alad V’s resources through multiple conflicts of attrition. The Board withdrew their support for Alad, who was forced to flee back to his Gas City on Jupiter. The Lotus was able to retrieve most of the Tenno cryopods while the fighting was ongoing.

Alad V managed to claim some of the warframe cryopods and continue his development of the Zanuka Project on Jupiter. He was soon able to create a working prototype, which he employed to hunt down and capture other Tenno so that he could continue to make more Zanuka proxies. He also auctioned off warframe components to other Corpus oligarchs in order to raise funding4. The success of Zanuka unnerved Chairman Frohd Bek, who feared Alad might one day take his position, so he disclosed the position of Alad’s Gas City to the Tenno during the Hunt for Alad V. The Lotus promptly dispatched a cell to Themisto to take Alad V out and halt further atrocities in the name of Zanuka.

The Gradivus Dilemma kicked off an open conflict between the Grineer and Corpus that appears to have continued in some form or another to the present day. The size of territory and resources held by each faction, and their relative parity in military might, require that the Corpus and Grineer work together when necessary in order to keep their economies and societies functioning5. However, they are quick to resort to violence if negotiations break down – as evidenced by Operation: Sling-Stone, the Gradivus Dilemma, and Vay Hek’s later declaration of war against Frohd Bek. Some sectors of the System seem to be embroiled in constant conflict, such as Phobos6, Europa7, and Lua8, and spontaneous Invasions occur frequently. While the Corpus generally have a more diversified economy, both sides are still heavily focused on warfare, weapons production, and military research, with entire moons and planets being devoted to singular military purposes. The war between the two factions appears to consume the majority of their bandwidth, so the Lotus directs the Tenno to make sure neither power achieves superiority over the other, lest their attention then turn to the civilian groups scattered around the System – or the Tenno themselves.


Project Tethra

Shortly after the Gradivus Dilemma, Councillor Vay Hek began to encounter increasing Tenno interference with his plans to solidify the Grineer’s position on Earth. His operation to unlock Gara’s power9 and his plans to clear Earth’s tropical forests to make room for Grineer settlements were both frustrated by the Tenno, under the Lotus’ guidance. In the wake of these defeats, he grew extremely spiteful towards the Tenno, and would soon develop a way to strike a powerful blow against an enemy that had so far proven quite elusive.

The first mention of Project Tethra came from Frohd Bek, as he was attempting to convince his son to join the Corpus Board of Directors: “Darvo, we are backed into a corner. Project Tethra will be the death blow! You are needed here.” It is unknown when the Corpus first learned about the project, but they were clearly concerned about the ramifications it could have for System-wide balance, and they were urgently preparing to meet a vastly improved Grineer military. It is worth noting two things: first, at no point do the Corpus ask the Tenno for help against this common enemy, as has happened many times both before and since; and second, no new tactics or innovations from the Corpus were forthcoming, and it is unclear if they would have been able to counter the looming threat in any significant way, despite their advance knowledge.

Not long after hearing the name “Project Tethra”, the Lotus was able to uncover its nature: the rebuilding of the Fomorian fleet, under Vay Hek’s leadership. Already, thousands of the massive ships were in production. The Lotus urgently issued Operation: Tethra’s Doom, with the objective of finding the ship construction site and sabotaging the nascent ships’ power cores. First, the Tenno penetrated the Grineer communications network on Earth, using new Interception protocols to gather data fragments, which the Lotus was able to combine to decrypt the locations of the Fomorian power cores. Once a core was located, the Lotus sent a strike team to hijack it en route to installation. In order to avoid catastrophic destabilisation, which would contaminate the area for generations, the Tenno commandeered the shipyard’s tram system to convey the Fomorian core to their own ship, which carried the core into deep space for safe disposal. Along the way, the Tenno fought off efforts by the Grineer to take back the core, or, failing that, to destroy the core in order to neutralise the Tenno (at the cost of the entire facility). This entire process (including the data interception) was repeated in order to hijack as many Fomorian cores as possible.

Partway through the operation, Vay Hek gleefully informed the Tenno that the cores they had been hijacking were actually auxiliary cores. The Lotus was able to use this information to modify her decryption algorithms and locate the main Fomorian shield cores, which the Tenno promptly pursued. Although Vay Hek upgraded the defences in his shipyard facilities, it was not enough to prevent the Tenno from sabotaging the bulk of his new Fomorian ships. Operation: Tethra’s Doom was an overwhelming success, although the Lotus cautioned that Hek was still able to build a number of Fomorians, which would pose a serious threat. She hinted that she was working on a plan to engage the Fomorians directly.

In the aftermath of his botched fleet reconstruction, Vay Hek grew increasingly paranoid. He concentrated his remaining Fomorian construction operations at the shipyards on Ceres (which the Tenno continued to disrupt) and dispatched his elite Prosecutor guards to provide security. The Tenno were able to kill enough Prosecutors and reverse-engineer their tracking beacons to locate Vay Hek himself, directing the project from the Grineer settlements in Earth’s forests. Although the Tenno tracked down Vay Hek and defeated his fearsome Terra Frame robotic exoskeleton, the Grineer Councillor ultimately evaded the assassination attempt and fled to safety.

Some time later, a mysterious associate (later revealed to be Baro Ki’Teer) contacted the Tenno, promising information about technology that could counter the Fomorians, in exchange for gathering cryotic. In Operation: Cryotic Front, Baro sent the Tenno to excavation sites on Earth, Mars, and Europa to extract cryotic from underground deposits. Although it later transpired that the Void Trader was using the cryotic for rather mundane purposes (to freeze rare jellyfish for transport), he nevertheless held up his end of the deal and provided the Tenno with weapons, mod technology, and, most importantly, a datamass containing information on an ancient Orokin technology called “Archwing”.

 It was also at this time that Vay Hek’s new generation of Fomorian ships came to be known as “Balor Fomorians”. What exactly the prefix “Balor” signifies is unknown, but these ships were reported to be more advanced than the first-generation Fomorians faced in Operation: Sling-Stone.

Most of the information on the Archwing datamass was corrupted, but it gave the Lotus a starting point. She spent incredible amounts of time and effort on researching and developing Archwing, even physical resources like cryotic, as noted during the Shifting Sands Tactical Alert. The Lotus knew that Orokin records of the Archwing could be found in abandoned Towers in the Void, and began to explore them, which drew the attention of Vay Hek. How he learned about the project is unclear, but it is possible that the Lotus’ efforts to research the Archwing were simply too big to remain hidden. Vay Hek immediately sent his forces into every Void Tower he could locate, using Torsion Beam Generators to open portals into the Void from Orokin ruin sites. Each of Hek’s expeditionary forces were led by a pair of clones: the vicious fighters Ven’kra Tel and Sprag. Their orders were to find information on the Archwing before the Tenno could – and destroy it.

In response, the Lotus launched Operation: Gate Crash. Unlike the Grineer, the Tenno could enter the Void directly (the exact method is unknown; perhaps using the Tenno-operated sections of the Solar Rail network?). The Lotus sent the Tenno into the invaded Towers from the Void side, where they fought their way to the portal and reversed its polarity. Then, the Tenno crossed the portal to the Grineer expeditionary bases, killed Ven’kra Tel and Sprag, and took the Void key that was powering the Torsion Beam Generator. After that, they used the Void key to sabotage the Torsion Beam device, and escaped back through the portal before it melted down. The Torsion Beam Generator overloaded, destroying the Void key and shutting down the portal, sealing the Grineer off from the Orokin Tower. This procedure had to be repeated for each Tower the Grineer invaded. Vay Hek’s Void keys were unstable, so crossing the portals they generated had detrimental effects to warframe performance – effects that compounded cumulatively with each additional mission.

The Grineer were invading Towers from bases on Earth, Mars, and Phobos, all of which were eventually disrupted by the Tenno, resulting in the destruction of the entire stockpile of Void keys. The loss of the Void keys triggered abatement of the over-exposure effects suffered by those Tenno who had run multiple missions. During their sabotage, the Lotus also encouraged the Tenno to explore the Orokin Towers for caches that contained resources and data. Enough caches were recovered that the Lotus was able to move forward significantly on the Archwing reconstruction. However, she cautioned that Vay Hek’s Fomorian ships were nearly complete.

Shortly afterwards, with the Archwing quest, the Lotus presented the Tenno with the blueprint for the Odonata model of Archwing – the culmination of Project Archwing. However, the component parts were still missing. The Lotus discovered that the Corpus had invaded the Void and secured an Orokin archive that contained the location of Archwing component blueprints. It is unknown if the Corpus knew what they were handling or what their motive was, but nevertheless, the Tenno responded by sabotaging their Torsion Beam Generator and shutting off the portal, much as they had done earlier in Operation: Gate Crash. They then accessed the Orokin archive, which gave them coordinates on Venus and Earth. Presumably, these were locations of Orokin military research facilities that were since buried beneath the surface. The Tenno used orbital excavators to extract blueprints for the Archwing components. Once they were secured, the Tenno finally were able to construct the complete Odonata Archwing, resurrecting a combat platform not seen since the time of the Orokin.

While Ordis ran extensive calibration tests on the ancient flight system, the Lotus sent the Tenno on a mission to collect intelligence from a Corpus scout ship reported to have information on the Balor Fomorians’ location. While the Tenno were investigating, Vay Hek announced that he was cancelling all contracts with the Corpus and declaring war against them. Shortly afterward, a Balor Fomorian warped into the area and began devastating the Corpus Obelisk – with the Tenno still inside. Both the Lotus and Frohd Bek (who was also on board) reacted with shock at the first exhibition of Balor Fomorian might, while Vay Hek cackled with glee. The Tenno was ejected into space as the ship decompressed and broke up around them, and the Lotus commanded Ordis to deploy the Archwing in order to save them. The Tenno utilised the Archwing to navigate the Obelisk debris field, staying behind cover as the Fomorian continued hunting for targets. Along the way, the Tenno fought off Grineer space combat units such as Dargyns, Dregs, and Zeplens. The Archwing, performing beyond expectations, was able to carry the Tenno to safety, where Ordis extracted them in the Landing Craft. The Lotus noted that, although Vay Hek had successfully brought Project Tethra to completion, the Tenno now had the capability to fight back, even alluding to other Archwing designs yet to be uncovered. The war had evolved.


Fomorian attacks

The Tenno had scant time to prepare before the Lotus detected a Balor Fomorian on an interception vector with Vesper Relay, near Venus. Shortly after the Tenno acquired the Archwing, the Lotus had completed construction on a series of Relay stations orbiting several of the System’s planets. Each Relay functioned as a haven where the Tenno could congregate and strategise, a forward base of operations for the Lotus, and – perhaps most importantly – a place for the Tenno to interface with civilian opposition groups like the Red Veil. The Relays held significant strategic and symbolic value, and greatly increased the Tenno’s standing as a major military and diplomatic power in the System. This, of course, made them prime targets for attack, and Vay Hek did just that in the ensuing Operation: Eyes of Blight.

The Lotus tracked the Balor Fomorian’s approach to Vesper Relay, and she coordinated one of the largest Operations in Tenno history. Intelligence reports (likely from Operation: Tethra’s Doom) had detailed the Fomorian power core schematics, and the Lotus was able to give all Tenno blueprints for a Disruptor gear item that could temporarily disable the omega energy shield protecting the Fomorian core. The Tenno gathered Omega Isotopes (a by-product of the Fomorian core) from the area near the Balor Fomorian, and used them to craft the Disruptor. Then, the Tenno attacked the Fomorian ship in a constant swarm of attrition. Each Tenno squad fought past Dregs and Dargyns, disabled the Fomorian’s shields, then penetrated the interior to disrupt the core’s Omega energy shield, inflicted as much damage to the core as possible using their Archguns, then fled before the energy shield regenerated. During the Fomorian’s 48-hour approach to the Relay, groups of Tenno repeatedly attacked the ship’s core. Vay Hek taunted the Tenno during their missions and berated his soldiers for their failures. In the end, the combined efforts of the Tenno were successful, and the Balor Fomorian exploded before reaching Vesper Relay.

However, this was only the beginning. Before the first Fomorian was destroyed, two more had already appeared, heading towards Strata Relay near Earth and Kronia Relay near Saturn. The Tenno had to continue gathering Omega Isotopes, crafting Fomorian Disruptors, and running sabotage missions against the Fomorian core for each new ship. Over the course of two weeks, 20 Fomorian ships in total arrived to threaten the Tenno Relays, representing the entire Fomorian fleet10. Although the Tenno fought valiantly, their attention was split among multiple threats, and in the end, 4 of the Fomorians survived to reach their targets, obliterating 4 Tenno Relays with their devastating siege lasers. Strata Relay near Earth was the first to be destroyed, followed by Leonov near Europa, Kuiper near Eris, and lastly, Vesper near Venus (which had survived 4 previous Fomorian attacks).

Of the 7 Tenno Relays, 4 were destroyed by Fomorians, leaving Larunda at Mercury, Strata at Saturn, and Orcus at Pluto as the only survivors. Of Vay Hek’s 20 Fomorians, 16 were confirmed destroyed. The status of the 4 Fomorians that managed to destroy the Relays is not known – they may have been destroyed after the attack, or they may have escaped. According to an intercepted message, the Twin Queens were highly displeased at the attack’s outcome, citing the immense cost of the Fomorian warships – the vast majority of which were destroyed. The Queens removed Vay Hek from his paramount military position in favour of Tyl Regor, and demanded penance from the Councillor. However, it should be noted that Vay Hek still appears to be in control of the Fomorian project, and Tyl Regor has not been observed leading similar initiatives.

In the aftermath of the Fomorian attack on the Relays, the Lotus commissioned a special cell of 8 Tenno to bring Vay Hek to justice. This became the Tenno’s first Trial: The Law of Retribution. The Tenno cell first sought Hek on Earth, his home jurisdiction, but he had anticipated them, and baited them into a toxin-filled trap while he escaped to a Fomorian production facility. The Tenno managed to destroy the Toxin Injectors and escape the trap, and followed Vay Hek to the Fomorian shipyard. There, they found evidence of Fomorian ships still in production, and decided to hijack a Balor Fomorian core in order to bait Vay Hek out. Although Hek sent the Grustrag Three to stop them, the Tenno were still able to escape with the core. The Lotus had tracked Vay Hek to Mars11, and with the Fomorian core no longer necessary as bait, she decided to study it instead of destroying it (as had been done with prior hijacked Fomorian cores). She sent the Tenno on to Mars to confront Vay Hek once and for all. Upon their arrival, they found Hek in his Terra Frame, backed by a surviving Balor Fomorian in orbit. The Tenno had to sabotage the power plants providing Vay Hek with invulnerability while avoiding orbital strikes from the Fomorian. Eventually, the Tenno were able to strike down Vay Hek’s Terra Frame, yet the Grineer Councillor managed to slip away at the last. However, in light of the victories won and the losses incurred on Vay Hek, the Lotus declared the Trial a success.


Aftermath and Conclusion

The destruction of the Balor Fomorian fleet and the sabotage of Fomorian production on all levels has crippled the Grineer’s ability to manufacture and deploy the behemoth ships. The Grineer can now only make meaningful progress towards building a Fomorian by invading and occupying Corpus territory and pillaging their resources (likely because of the high oxium requirements12). Once a Fomorian is built, it is sent to destroy a Relay (still under Vay Hek’s command), but without the combined assault seen during Eyes of Blight, they are much easier for the Tenno to handle, and the Tenno have never failed to destroy these new Fomorians before they strike.

Although the Twin Queens allegedly replaced Vay Hek with Tyl Regor, Regor has not been seen leading military initiatives of the same scope and vision as Project Tethra. His subsequent activities have involved archaeology and research in genetics and cloning, and while his goals could prove transformational for the Grineer race, they lack the dramatic zeal of Vay Hek’s plans, and he certainly has not sought out conflict with the Tenno or Corpus. The larger military and strategic goals of the Grineer Empire currently lack a clear definition.

The war between the Grineer and Corpus continues to rage over certain flash-points, but many of the borders seem to be largely set at this point. During the New War, the entire System saw an unprecedented level of cooperation as Grineer, Corpus, and Tenno united to fight the Sentient invaders, and for the first time, Grineer Galleons flew side by side with Corpus Obelisks in the Veil Proxima (notably, there were no Fomorians observed during the New War). However, this combined fleet failed to stop Ballas and the Sentients, with the Grineer and Corpus suffering massive losses, the scale and nature of which are still yet to be determined. After being forcibly enslaved under Ballas’ Narmer Empire and subsequently liberated by the Tenno, the alliance has dissolved, and the Grineer and Corpus are once again at odds. It remains to be seen how the System will recover from this turbulent period and what, if any, changes the “Narmer interlude” produced in the pre-existing order. But for now, all we can do is study, analyse, and above all, wait.


[Navigation: HubDiscussion → Timeline: The Grineer-Corpus War and Project Tethra]

  1. “The Corpus are a dominating proto-corporation of humans that maintain and operate the trade routes of the Solar Rails.” (old Corpus faction description)
  2. As noted during Operation: Sling-Stone.
  3. Originally Phobos; presumably retconned to Mars when the Grineer Settlements tileset was moved from Phobos to Mars in Update: Spectres of the Rail.
  4. As seen in The Profit trailer.
  5. Cephalon Cordylon describes that the Grineer and Corpus use the same currency in order to trade with one another. Grineer-Corpus cooperation is also discussed on the Radio Scanner.
  6. “Phobos has always been a hotly contested area. Skirmishes between the tireless Grineer and Corpus factions occur in orbit and on the Martian moon surface.” (Phobos Cephalon fragment)
  7. “The scattered remains of a vast Corpus Obelisk litters the snowy landscape while the battle above wages on” (Europa Cephalon fragment). Also, an Obelisk and Fomorian can be observed engaged in battle in the skybox.
  8. Although no conflicts have yet been observed, both Grineer and Corpus are present on the moon, and engagements are likely to occur.
  9. The Saya’s Vigil quest, though added later, is presumed to take place around this time.
  10. Twin Queens: “You have exhausted our entire Balor fleet…” (Eyes of Blight aftermath)
  11. Originally Phobos; presumably retconned to Mars when the Grineer Settlements tileset was moved from Phobos to Mars in Update: Spectres of the Rail.
  12. Twin Queens: “Do you understand how much oxium goes into a single Fomorian?” (Eyes of Blight aftermath)

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