Now that MechWarrior Online has finally been revealed, I decided to write up a little primer on the background of the BattleTech universe, up to 3048 which is when the game will be set. I know there's a lot of people out there who have played some or all of the MechWarrior games but might not have any clue of what the lore behind the games is all about:

The BattleTech timeline begins with the end of the Cold War in the late 1980s, when the Soviet Union imploded into violent civil war and the Western powers grew into the Western Alliance. Soon afterwards, two enterprising scientists came up with a theorem for warping space in order to facilitate faster-then-light jumps between star systems, which eventually became the Kearny-Fuchida jump drive. JumpShips went out from Earth to colonize neighboring planets. The K-F jump drive requires a one week recharge between jumps, where it unfurls a massive solar sail in order to drink up the solar energy of nearby suns. Later in the time of the Star League, Lithium-Fusion batteries would enable jump drives to store an extra charge, enabling two jumps before having to recharge. However in general, because of the one week recharge between jumps, travel through the Inner Sphere is relatively time consuming compared to other scifi universes. The only way to provide for fast travel comes in the form of command circuits, which are pre-planned groups of JumpShips that are stationed one jump apart. Thus, when one ship jumps from one system to the next, their cargo can immediately be transferred to the next ship which jumps to the location of the next JumpShip, and so on. However, this takes many JumpShips and resources, and is thus only used for the most extreme emergencies, or by the highest members of the House leadership.

Each star system had two jump points, which are the zenith and nadir of the star's gravity well. These are normally the only places a JumpShip can jump to, making invasions relatively easy to spot. However, there are also other points called pirate points, where a JumpShip can attempt to jump to and avoid detection. These are riskier, as they can result in a misjump. Many planets that were colonized had a dearth of water, which prompted some JumpShips to start ferrying large chunks of comets to supply the colonies with fresh water. These were called Ice Ships and helped support the rapid expansion of humanity across the cosmos.

JumpShips also carry DropShips, which are the actual ships that land on planets and drop 'Mechs and vehicles and infantry. Some DropShips are dedicated aerospace fighter carriers, like the Leopard CV. In the Inner Sphere of 3048, the primary DropShips used for carrying BattleMechs are the Leopard, the Union, and the Overlord. The Leopard is the smallest of the three and can carry a lance of 'Mechs and a pair of aerospace fighters. The Union can carry a company of 'Mechs, and the Overlord can carry an entire battalion.

Eventually, these colonies would band together and form their own autonomous states, which became the five major House States. Terra and its nearby neighboring planets formed their own alliance called the Terran Hegemony, under the leadership of charismatic Fleet Admiral James McKenna.The Inner Sphere became the name of the region of space surrounding Terra to a radius of 500 light years, comprising of all five States. Because such vast regions of space were inherently difficult to rule by democratic means, all the states reverted to ancient feudalist systems of hereditary leadership, thus establishing the Houses.

In time, all the Houses began to war amongst each other for control over planets and resources. Chancellor Liao of the Capellan Confederation, distraught at all the civilian deaths resulting from these battles, gathered all the leaders of the Houses together to sign the Ares Convention, a treaty which set rules in place for civilized warfare, and outlawed orbital bombardments and nuclear weapons. While this cut down on civilian casualties, it also made war much more acceptable for solving diplomatic issues, and this period of time is referred to as the Age of War.

During this Age, the Terran Hegemony invented the very first BattleMech, the Mackie. These massive war machines could not have been invented without the development of proper myomer, or artificial muscles activated by electricity. Project Musclebound created the first successful myomer and enabled 'Mechs to move and support their great weight. The Terran Hegemony fiercely guarded the secret of 'Mech development until the Lyran Commonwealth stole plans for them. Soon, they spread and every House state had their own army of 'Mechs, the kings of the battlefield.

The basic organization of BattleTech revolves around the lance, or four 'Mechs. Three lances make up a company, and three companies make up a battalion. Three to five battalions make up a regiment. A Regimental Combat Team in the era of the Star League was composed of four regiments of 'Mechs. Later, during the Succession Wars, the Federated Suns would create a new Regimental Combat Team that was made up of one regiment of 'Mechs, and three or four regiments of support vehicles, fighters, and infantry. Larger organizations exist in the form of brigades, divisions, and armies. Only during the time of the glorious Star League were such massive formations commonly used.

Then came a Golden Age for all mankind, where all the House states united with the Terran Hegemony in a Star League under the leadership of the Cameron family, and people's lives were better and advanced technology flourished. In this time of miracles, new advanced weapons systems were created for Mechs, such as Headhunter missiles, extra-light fusion engines, anti-missile systems, and even Active Camouflage.

Entire Space Defense Systems for planets were created, with batteries of ground lasers and missiles supported by fleets of automated AI WarShips called Caspars, which packed the firepower of a cruiser with the maneuverability of a frigate. Defensive fortifications built inside of mountains called Castles Brian were also created, which could hold entire regiments of Mechs and stockpiles of ammunition.

However, a final impediment to a united Mankind still remained, in the form of the various Periphery states. The Periphery was the outer region of space that lay outside of the Inner Sphere, and had filled with malcontents, bandits, and rabble that had been shipped out of the House states. In time, they had formed their own states, though these were not as powerful as the House states. The Periphery states were comparatively weak, though protected from being conquered by the House states because of the Piranha principle. This was the idea that if a House did launch a major offensive to conquer a Periphery state, they would be leaving themselves vulnerable to attack from a neighboring House. Thus, the Periphery remained safe, until the five Houses united in the Star League.

First Lord Ian Cameron would not rest until all of man had joined in his grand alliance. The Star League issued the Pollux Proclamation, which was a declaration of war on the Periphery. While initially believed to be an easy endeavor, the Reunification War, as it became known, ended up taking over 30 years and cost the Star League Defense Force dearly. Periphery citizens used terrorism, poison gas, sabotage, and even human wave attacks to defend their planets against BattleMech regiments. However, the SLDF eventually succeeded and the Periphery was brought into the League. Humanity was united and an era of prosperity began. And in that time of great deeds stood the greatest warrior of all time, Aleksandr Kerensky.

But all good things must come to an end. In 2751, the First Lord of the Star League, Simon Cameron, was killed in a freak IndustrialMech accident, and his son Richard was still too young to take up the reins of power. The Council appointed General Kerensky of the SLDF to be the boy's Regent until he was 18 years old. While Kerensky tried to influence the young Cameron in a positive manner, Richard instead became good friends with the leader of the Rim Worlds Republic, Stefan Amaris. Amaris (looking like a fat Genghis Khan) appeared to be friendly and charming, but secretly harbored bitterness and hatred for the Camerons, who had conquered the Republic long ago in the Reunification War. Once Richard Cameron became old enough to assume the position of First Lord, it became obvious that he had turned into a naive, arrogant, and deeply conceited individual, easily influenced by Amaris's suggestions.

The flames of rebellion began to spring up on Periphery worlds, with the most serious being on New Vandenberg. The Star League had long taxed the poor Periphery states to support its lavish projects and military expansion. These rebel attacks were instigated by Amaris, who secretly supplied 'Mechs and training to the rebels. With Star League bases in the Periphery being hammered and even nuked by the insurgency, and insurrections flaring up on dozens of more worlds, Kerensky had no choice but to send most of the entire Star League Defense Force, the strongest military ever assembled in human history, to retake the Periphery and stamp out the rebels. However, this meant leaving the Terran Hegemony woefully undefended. Stefan Amaris voluntarily offered to send his Rim Worlds forces to help defend the Hegemony in Kerensky's absence, which Richard Cameron eagerly agreed to. Amaris's forces moved in to man the positions left by the SLDF and began asking many questions about the Castles Brian and Space Defense Systems in operation.

With all of his forces in place, Amaris arrived in Richard's chamber in Unity City and presented his close friend with a gift, a jeweled laser pistol. The young First Lord was overjoyed with his new gift. Amaris explained that it was a very special pistol and then pointed it at Richard's head and fired. He immediately ordered his forces to assume defensive positions and take over the palace's security systems. Unknown to them, the glint of the laser discharge had been automatically picked up by a security camera and alarms went off throughout the palace. Palace Guards raced down the corridors to the chamber, only to be cut down by the hidden lasers of the security systems. Three of them made it to the door only to be killed by a thrown grenade. The elite Royal Black Watch Regiment, the personal bodyguard unit of the First Lord, was ambushed by Rim World Republic forces but nine members made it to their 'Mechs. All Royal Black Watch members had been graduates of the Star League's Gunslinger program, a graduate level MechWarrior program dedicated to teaching dueling tactics, and analogous to the Top Gun program for US naval fighter pilots. They marched toward the Court and prepared to defend their First Lord, unaware he was already dead. Making their last stand on a narrow bank, they chewed up wave after wave of Rim Worlds Mechs. Unprepared for the furious defense, the Rim Worlds forces pulled back. Then two aerospace fighters flew overhead. A tremendous nuclear explosion followed. The Royal Black Watch Regiment was no more.

More palace guards flew on jetpacks toward the chamber. The few that survived managed to plant a bomb on a wall and detonate it. Amaris himself narrowly avoided injury because a heavy oak chair protected him from the blast. Amaris's reinforcements then arrived and killed the last remaining guards. Amaris then issued an ultimatum and demanded that SLDF forces throughout the planet lay down their arms, or he would kill the First Lord. Most agreed, and were forced to dig their own graves before being executed by Amaris's forces. Throughout the Terran Hegemony, Rim Worlds forces used surprise to overwhelm and defeat the SLDF defenders. In many instances, Amaris's forces resorted to nuclear weapons to destroy entrenched defensive positions.

Amaris then sent a message to General Kerensky, asking him to join his side and forget about his duty to the Star League. Amaris now controlled all of the resources and defenses of the Hegemony, including the formidable Space Defense Systems. Kerensky immediately ceased all hostilities with the Periphery states, and gathered his entire force, more then 300 divisions, to invade and take over Amaris's Rim Worlds Republic. With most of Amaris's forces now in the Hegemony, the Republic was easily conquered. Kerensky needed a base of operations to prepare for the war to retake the Hegemony. He also asked the five House states to join him in wiping out the traitor Amaris, but every House refused, preferring to wait and see which side would emerge victorious. Ordinary citizens in the House states however, felt outraged by the usurping and voluntarily joined Kerensky's army. These were formed up into volunteer regiments and often suffered the greatest casualties in the conflict. Some SLDF forces, outraged at the thought of their oppressed homeworlds, would not wait, and headed straight back to the Hegemony as soon as they heard of the betrayal. The 34th Royal BattleMech Division was one and was wiped out by a Space Defense System over Epsilon Indi.

Kerensky split his army into three task forces to retake the Hegemony. Amaris had managed to hire 40 divisions of mercenaries, and these along with the Castles Brian and Space Defense Systems made him dangerous. There was no way to regain control of the SDSs, because Amaris had changed the passcodes, so the only way was to fight them head-on. For every planet retaken, more then three SLDF WarShips were lost. The signs of Amaris's reign were also sobering. Many planets had suffered mass rapes, starvation, and slave labor at the hands of Rim Worlds forces, while others had simply been nuked into oblivion. But after long fighting, all three task forces moved inward and gathered in an interstellar ring, as Amaris pulled all of his remaining forces back to Terra. He ended his meeting with his officers by remarking that “I can’t look at the stars anymore. Every time I do, they seem to constellate the face of Kerensky.”

Kerensky had lost more then a third of his forces and half his navy. The only task that lay before him was to retake Terra, the most heavily defended place in the universe. Terra was guarded by the Reagan SDS, many times bigger and stronger then any other SDS. Ten immobile battle stations were stationed at the jump points, and were destroyed by remote controlled DropShips loaded with explosives. Kerensky had his entire naval armada jump in afterwards. There were also over 250 Caspar drones in orbit around Terra. Kerensky ordered 40 of his WarShips to jump a second time to a pirate point ahead of the main fleet, in order to wipe out as many of the Caspars as possible. For two days, the Star League fleet fought the Caspars, eventually succumbing but destroying over 100 of them in the process. The Sovetskii Soyuz, winner of the Star League's Martial Olympiad, was the final ship to fall. The remaining Caspars immediately headed for the main fleet, focusing on the troop transports. Entire divisions of 'Mechs were wiped out in a single pass. Eventually, the Caspars lost more of their numbers and lost unit cohesion. Star League WarShips were also ordered by their captains to ram into Caspars if they were grievously wounded. The tide turned, and the Caspars were defeated. The SLDF turned its attention toward the 30 ground laser and missile batteries on the planet. Aerospace fighters launched from their ships and made steep diving runs to avoid being hit. Many were shot down anyways by Amaris fighters and the SDS system, but enough survived to wipe out the batteries.

DropShips landed on multiple continents. Kerensky himself landed with a division to retake his hometown of Moscow. Rim Worlds forces used entire city populations as human shields. To save lives and time, Kerensky focused on Unity City, located in North America. A massive force crossed the Bering Strait, while thousands of dropships landed in Mexico. SLDF forces fought to establish a foothold on Alaska as Amaris divisions tried to push them back into the ocean. Eventually, the SLDF arrived in Unity City, but found out that Amaris had instead moved to the Imperial Palace, a retreat Richard had built for him in the Canadian wilderness. Aleksandr Kerensky in his olive drab Orion personally led the charge, outrunning multiple pillboxes and kicking open the gates to the palace. Stefan Amaris then surrendered with his family and agreed to order his forces throughout the Hegemony to surrender.

SLDF forces opened up the Throne Room of Unity City and witnessed a gruesome sight. Apparently in the early years of his usurpation, Stefan Amaris had gathered up every member of the Cameron family and slaughtered them in there, then sealed the room. When Kerensky saw the sight for himself, he immediately had Amaris and his family executed. Then began the long and difficult path of rebuilding. Meanwhile, the five House lords had begun to squabble over what to do. Each one argued that they should be the new First Lord, as there were no more Camerons. In the end, they came to no agreement except to dissolve the Star League. Each returned to his state and began building up forces. General Kerensky, distraught at the end of the Star League, still had the entirety of the SLDF backing him in whatever he planned to do. Many speculated that the general would lead his army to conquer all of the Houses and forcibly reuniting them under his banner. In the end, he came up with the plan for Operation Exodus, and in 2784 the entire SLDF and their families boarded their massive armada and jumped out of the Inner Sphere, past the Periphery, and into the history books. No one knows where they went, but just outside our sphere of light, men and women may well be watching and waiting for the day of return.

With the disappearance of Kerensky and his SLDF, the five Houses declared war on each other and so began the Succession Wars, which gradually eroded the knowledge and technological advances of the Star League. WarShips, massive JumpShips with naval weaponry and heavy armor, were eventually all destroyed and the facilities and knowledge of how to construct them were lost. The remaining JumpShips, unarmed and produced at a snail's pace by each House, became irreplaceable and were ruled as noncombatants in any conflict. The Star League's advanced weapons and technology, lost in the chaos of the wars, became known as lostech. Ancient memory cores and books from the Star League era are sometimes found in obscure caches and incredibly valuable. Hanse Davion himself led a raid on Halstead Station to retrieve a cache of technical books. With these books, he founded the New Avalon Institute of Science, a university dedicated to the advancement of science and technology in the Federated Suns.

The last remaining vestige of the Star League, its interstellar communications system of hyperpulse generators, was turned into ComStar by Jerome Blake, the Star League Minister of Communications who remained behind when Kerensky left in the exodus. He dedicated his new organization to maintaining technology in this new and barbaric era. His successor, Conrad Toyama, would convert ComStar into a religious organization devoted to worshipping lost technology and keeping it out of the hands of the Houses. The philosophy became one of watching civilization crumble and collapse into the dark ages, where the stage would be set for ComStar to emerge as humanity's savior. ComStar's secret intelligence organization, ROM, was often tasked with black ops, assassinating any House scientists that succeeded in retaining or advancing technology. While remaining neutral in the Succession Wars, ComStar did have the power to Interdict, or shut down communications between planets. This was crippling for any House engaged in a campaign against another House. Without communications, regiments couldn't receive orders or coordinate with other regiments.

In 3048, the major states of the Inner Sphere are:

Federated Suns: House Davion. They've mostly been the nominal good guys of the Inner Sphere. Has a bit of a British heritage flavor, but it's not all that evident. Ruled by a First Prince. In 3048, this man is Hanse Davion, otherwise known as "The Fox" for his cunning. His older brother Ian was First Prince before being killed by Combine forces on Mallory's World. The Capellan Confederation plotted to replace Hanse Davion with a doppelganger loyal to House Liao, but this conspiracy was foiled by Ardan Sortek, and in response Hanse Davion invaded the Capellan Confederation, launching the Fourth Succession War. Also part of the Federated Commonwealth, a grand alliance with the Lyran Commonwealth. Operates Regimental Combat Teams, a combined arms unit composed of one regiment of Mechs backed up by a few regiments of vehicles, aerospace fighters, and infantry. Sworn enemies of its neighbors the Draconis Combine and the Capellan Confederation. Capital world is New Avalon, which also houses the New Avalon Institute of Science, or NAIS. This is one of the few remaining universities which retain and invent technology. Also home to the mysterious Dr. Banzai, inventor of the Hatchetman. Their special forces unit is MI6, the Rabid Foxes. Generally considered the most powerful Successor State.

Lyran Commonwealth: House Steiner. A state that comes from a heavy Germanic background. Mostly known for having both amazing merchants and also horribly incompetent social generals. Prefers mostly heavier Mechs, yet suffers many defeats because of this lack of mobility. Two exceptions to this tendency are the Tamar Tigers and the Stealths, two regiments renowned for their brilliant guerrilla tactics. Owns and defends the highly important factory world of Hesperus II, responsible for most of its Mech production. Allied with the Federated Suns under the Federated Commonwealth. Ruled by an Archon, currently Melissa Steiner, who's married to Hanse Davion. Utilizes the feared internal intelligence/terrorism arm called Loki, which is counterbalanced by the civil rights whistleblower group of Heimdall. Capital world is the icy planet of Tharkad. Bordered the Draconis Combine and the Free Worlds League, through recently the Free Rasalhague Republic was created as a buffer state between the Combine.

Draconis Combine: House Kurita. The Japanese successor state, this place is a lot like World War II-era Japan: militant. Often simply referred to as The Dragon. Heavily influenced by Japanese culture and traditions, which is strange considering that most citizens of the Combine are not of Japanese ancestry. Most Combine warriors are heavily devoted to the Bushido ideal, and regard themselves as samurai. Thus, they tend to prefer one on one duels, which are seen as more honorable. They also tend to be more skilled at Mech piloting because of this. Ruled by a Coordinator, currently Takashi Kurita, though his son Theodore has gradually assumed most of the real power. Takashi infamously declared Death to Mercenaries, after having a bit of a falling out with Wolf's Dragoons. Recently, Theodore created the Ghost regiments, composed of yakuza, women, and other unwanted elements of society, in order to bolster his forces against the combined juggernaut of the Federated Commonwealth. The Ghost regiments were instrumental in successfully defending the Combine during the War of 3039. Fierce enemies of its neighbors, the Federated Suns and the Lyran Commonwealth. Once responsible for the massacre of Kentares VI during the First Succession War, which resulted in the slaughter of more then 90% of the planet's population, after Coordinator Minoru Kurita was killed by an enemy sniper. The capital of the Combine is Luthien, or the Black Pearl. Utilizes the special forces of DEST, or Draconis Elite Strike Teams. DEST is comprised of warriors trained in all manner of infantry combat, Mech piloting, counter-terrorism, sabotage, katana duels, etc. Basically, they're amazing.

Free Rasalhague Republic: The brainchild of Theodore Kurita, this buffer state between the Draconis Combine and the Lyran Commonwealth made moot all of the Commonwealth's gains during the Fourth Succession War. Mostly composed of a Scandinavian populace, which had resisted assimilation into the Combine. Currently ruled by Elected Prince Haakon Magnusson.

Capellan Confederation: House Liao. The Chinese successor state. This is the smallest and weakest of the five Houses of the Inner Sphere. Ruled by a Chancellor, currently Romano Liao, a crazy woman. Was savaged by the Federated Commonwealth during the Fourth Succession War, and lost many worlds that subsequently became the St. Ives Compact. The capital world is Sian. Uses the supremely feared special forces named Death Commandos, trained in Mechs and black ops. Death Commandos are utterly devoted to the Chancellor and also utterly ruthless and will not hesitate to hold a planet hostage to achieve their goals. Borders the Federated Suns, which has tried throughout the Succession Wars to bring it to its knees.

The St. Ives Compact: The Federated Suns dealt a tremendous blow to the Capellan Confederation in the Fourth Succession War. Afterwards, most of the planets liberated by the Suns formed their own mini-state called the St. Ives Compact, ruled by Romano's sister Candace Liao, who defected and allied herself with House Davion. This state is basically a puppet extension of the Suns but tries to retain its uniquely Liao culture and systems of governance. Just think of this place like Taiwan.

Free Worlds League: House Marik. The most democratic of the Houses, this state is ruled by a Captain-General who comparatively holds much less power then the leaders of the other states. The current Captain-General is Thomas Marik, or someone who greatly resembles Thomas Marik. Known as an industrial powerhouse, the Free Worlds League is also located in the most boring region of the Inner Sphere and thus doesn't really do much of anything. Borders the Lyran Commonwealth and the Capellan Confederation. Capital world is Atreus. Their intelligence service is SAFE, widely considered the worst intelligence agency in the Inner Sphere.