The actual war on Barooom started after several major warnings had been ignored by the Imperial governer who didn't want to provoke an attack, so refused to allow mass movement of reinforcements. The Orcs seeing this as a weakness launched a gigantic offensive against the human settlements. After massive territorial gains against the limited human defence forces a distress signal was sent and Imperial reinforcements arrived.
Alzee, the Ork commander had a dream of the Ork god Mork fighting against a Space Marine. The two fought each other to a standstill and it seemed that Mork might lose when a Chaos Daemon appeared and stabbed the Marine in the back, allowing Mork to win. Orks are deeply superstitious and the following day the Orks sent emissaries to the nearby planet of Beeross to ask for Chaos assistance. The Dark Ones arrived led by the brilliant young commander Jurghen Strong, however the advance could not continue and they were held up in another battle to the north of the capital. It took another Ork offensive to breakthrough this time against an Imperial force which included Eldar forces sent from the Iyandun craftworld to help battle the Daemon armies. With poor communication between the Imperial and Eldar allies, Eldar troops attacked the Kavadah Space Port, two days after it had been recaptured by Imperial forces. The Space Marines however had orders to resist them by force and they successfully defended the port in a fierce battle with Eldar units, which was a tragic friendly fire incident. The start of a new Ork/Chaos offensive meant the squabbling Imperial and Eldar commands were forced to join forces and in an indecisive battle to the east of Kavadah the advance was finally halted for good.
Using Space Marine units from within Kavadah the Imperial Governor now ordered a counterattack which forced the Orks to withdraw. A further breakout to the north resulted in another Ork withdrawal. This massive retreat continued until the Orks decided to hold the city of Nataska on the river Yule. Reinforced by a Gargant Big Mob the Orks inflicted heavy casualties, but the arrival of the Veteran Space Marine Company from dropships was unstoppable and the Orks were defeated and forced back. The hard fought battle however drained the Space Marines of vital reserves. Keen to exploit the weakness and hoping to relieve the pressure on the Ork army, the Chaos forces launched a counterattack which resulted in the indecisive battle of Kachave. The Space Marines diverted forces and attacked the Chaos army defeating them and sending them reeling. However the Chaos offensive had bought time for the Orks to reorganise and the large number of Space Marines currently engaged against Chaos meant the Ork front was weakly held. Alzee launched his attack the following day and smashed his way past the Imperial front line, being brought to a stop with a brilliant defence by the Golden Phoenix Chapters Veteran Company. The Space Marine Veteran Company then followed up their success with another victory over the greenskins before the weather turned hostile and brought hostilities to an abrupt halt.
It took almost three months for the weather to improve sufficiently for the massive armies to operate effectively again. Seizing the initiative Chaos forces launched a three-pronged attack against the Eldar territories in the North and the Space Marines in the South. Whereas in the north the attack made little gains, the attack on the Imperial territories turned into a massive drive after the Space Marine disaster at the Battle of Numaga. However Ork attempts to widen the offensive in their sector failed in a bloody battle outside the city of Centauri. The Chaos drive was relentless but in the end it over stretched itself and a small Chaos scouting force was heavily defeated by a Space Marine rearguard action. Then the border fortress of Lucknee XII was assaulted by Chaos forces, although the defending Space Wolves fought heroically meaning all attempts ended in a deadlock. The Chaos commander, Jurghen Strong, then called on the Orks to join with him and try to divide the Eldar and Imperial armies and destroy them piecemeal. The offensive was launched against the city of Pius jointly defended by the Eldar settlers and several Space Marine companies deployed to stiffen the defence. Despite overwhelming pressure the line held against the Ork and Chaos battering and they attackers were forced to retreat with heavy casualties.
After intense negotiations Squat forces from Forgrell landed on Barooom in support of the Imperial forces. Their arrival saw them thrust into battle against a small Chaos force, which was quickly destroyed in a brilliant victory at Bleewoss. The Squat forces then attacked the Chaos units gathering to recapture the city, and won another victory. The Chaos forces looked doomed, with their Ork Allies unable to help and surrounded by a tighter and tighter Imperial and Eldar force. Jurghen Strong decided on a decisive drive and gathered all the Chaos forces together and launched a massive attack on an Imperial force preparing to make its own attack. Despite inflicting massive casualties the Chaos forces could not break through and were forced to evacuate with the heaviest casualties ever seen on the planet. One heavy transport carrying perhaps as many as 5million minions was destroyed just after take off and crashed into the shattered remnants of the city.
With the Chaos forces defeated and the Orks at their mercy the war should have ended there and then, but under direct orders from the Imperial Palace, a whole chunk of the Imperial forces were taken off the planet to counter a new Tyrannid threat, leaving the Golden Phoenix Space Marines and the Cronan Imperial Guard regiments. It was felt that these two massive forces alone could destroy the Ork menace, despite being outnumbered by at least thirty to one. The Ork strength was shown in their unsuccessful but massive attack on Lucknee XII. The Squat Army, who had become increasingly frustrated at the bit-part their forces were playing began to become more and more uneasy. There were those who had fought the Imperium and knew the treachery that Imperial Governors could do. Worried that the Imperial Commander would call off the campaign and let the Orks off the hook some Squats gathered together and formed a rebel group. In a small incident a collection of rebel Squats turned and attacked the Imperial Headquarters in Kavadah hoping to capture the Imperial Governor and use him to order the Imperial troops to finish the Orks off. Although the attack ended in a stalemate, Commander MacK felt the need to give his assurance that the campaign to end the war would mean forcing the Orks off the planet, and the rebel Squats were allowed to rejoin their regiments. Within days the Space Marines were given the orders to advance into Orkland. After a long and hard fought battle, the Space Marines broke through the Ork front line. The offensive continued after another battle was fought and won by the Emperors troops around Blockhowe. But these victories revealed their opponents increasing effectiveness as military powers and the Space Marine offensive finally fizzled out after a bloody deadlock developed against a well-prepared and intelligently led Chaos force.
Dangerously over stretched the lead elements of the Space Marine attack were then counter attacked by a new Chaos army in a surprise attack that inflicted heavy casualties. However a surrounded Chaos fortress at Degrel surrendered after an assault by reserve units of the Imperial Army. This victory however left forward Space Marine units unsupplied and a massive Chaos attack on the city of Knightsvol ended in an inconclusive battle. Ork attacks increased as well. In two big battles to the north the greenskins were defeated in the battle of Fujitsar and compelled into a deadlock at Icle. The uneasy alliance of Orks and Chaos ended however with a dispute between two regional commanders which resulted in a battle and an Ork victory. The respite given to the Imperial troops was short-lived however and they were heavily defeated in a Chaos victory at the battle of Legon. Furthermore an Ork attack on Reob V was brilliantly led and the Squat and Imperial force were forced back with heavy casualties. The whole nature of the war had changed and the Imperial forces now found themselves fighting experienced and intelligently led foes. The Chaos offensive encircled a massive Imperial force in Bletax that was heavily defeated and forced to evacuate. Meanwhile the war against the Orks went much better. After repelling a heavy greenskin attack on the city of Droiden the Orks were pushed out of one territory after another with a series of small scale victories. Chaos became the dominant enemy and a Space Marine force was almost completely decimated at the battle of Tofl, but a Squat-Imperial counterattack plugged the gap. A small Ork force then pushed back a Space Marine force, but were stopped by a battle at Vaindro that inflicted heavy casualties on both sides.
With the Ork and Chaos alliance at an end, the Orks somehow managed to negotiate a bargain with the Eldar mercenaries on the planet and the two forces won a brutal battle against Imperial forces, which were rolled back. The next day a small Ork recce force ran into the rearguard of the retreating Space Marines. In one of the longest battles ever seen, the battle of Mobile was won by the Emperors troops, allowing the city to be successfully evacuated and its garrison be used to plug the gap. A Chaos led rebellion at Hysmit was quickly put down by the Golden Phoenix Veteran Company. The Orks now chose the time to launch a massive new offensive, bigger than anything they had tried before. The city of Knightsvol fell after a long and bloody battle, but the Eldar mercenary attack on Ekok to the south failed to break through and were defeated, ending the Ork-Eldar alliance. Unworried by this setback the Orks continued their attack, and won another bloodbath at Vigel. They then captured the outskirts of the Imperial capital Kavadah. Only at the battle of Lundi was the Ork offensive stopped, but not driven back. Chaos forces then offered their assistance to the Orks, which was accepted and the Dark forces launched a bitter attack on Erni, but failed to capture the city. Only when Ork forces arrived and helped in a new assault did the city fall, and in the process a massive Imperial army was destroyed. Chaos troops now redoubled their efforts to capture the city of Holo, but were comprehensively beaten. The Dark forces were then counterattacked by a Squat army that was compelled to withdraw after inflicting heavy casualties. Chaos attempts to take the fortress of Lucknee XII were also unsuccessful. At Bleewoss Ork attempts to destroy the remaining Squat forces on the planet were defeated. Ork units were now beginning to be equipped with three Mega-Gargants that had been built with incredible speed. Accordingly the Firebird Titan Legion began to deploy more powerful Titans of their own to meet the new threat. When Commander MacK asked for the right to deploy Imperator Titans, the Imperial Palace sent an order stating that it was obvious that the Imperial troops on Barooom were doomed, and as such only one Imperator would be dispatched. Commander MacK was promoted to Lord Commandant and made Supreme Commander of the newly formed Imperial High Command , to help deploy forces more efficiently. After withdrawing from the dangerously exposed city of Hightler, MacK decided to test the Imperator titan in a large scale battle fought against Chaos. Although awesome Annilhator failed to break through and the battle ended in a stalemate. But Chaos attempts to counterattack were also inconclusive. Again the Imperial Alliance was then given time to regroup after an Ork force mistook a Chaos force for Imperial and began attacking them. The Squats took the initiative and launched an attack against an Ork force that was reinforced by a Mega-Gargant(KizMeButt). The Squat attack broke through and the MegaGargant was forced to retreat eastwards. The other two MegaGargants MuvverKrusher and SukMaCheek were deployed along the Imperial border waiting for the order to attack. Annilhator the Imperator was deployed in Kavadah protecting the capital.
In an amazing show of courage and hoping to split the Squat and Imperial forces the MegaGargant advanced on the city of Liather with no support from any other units. Seizing the chance to bring down the odds waged against it, Annilhator moved against it and in a desperate conflict destroyed the massive Ork machine and most of the city as the massive titan exploded. However the loss of one of their machines held up all further Ork attacks. For the moment the Imperial Alliance was saved. A sudden Ork-Chaos counterattack however did finally halt the Squat offensive in the north. In a brilliant strategic battle however fought near the city of Litrer, Annilhator with Squat forces moved against the Ork Mega-Gargant Suk Ma Cheek, destroying it and forcing the Chaos troops to the south to evacuate or be destroyed. Eldar units however prevented a Space Marine army from taking the spaceport at Trondheim, a defeat that encouraged the Imperial High Command to ask for their help. After being awarded an alliance the Eldar troops were thrust immediately into battle with the Imperial troops against a Chaos force. The attack however failed to achieve its objectives and the attack petered out. With fresh troops the Imperial commander tried again the following day and this time forced the Chaos troops to be pulled out. Although the battle plan had failed in the face of stiff Chaos counterattacks, the new tactics employed by Lord Commandant MacK of ignoring the infantry, and concentrating on the machinery, seemed to have been justified. The following day a Chaos stronghold was reduced to rubble in the heaviest bombardment ever seen on the planet. The tactics used to capture the stronghold were also revolutionary. By isolating the strong points and bringing massive artillery support to bear on them, the brilliant defences of the Chaos commander were bypassed or ignored. Again friction between the Orks and Chaos troops broke out in an open battle that ended with the two agreeing to concentrate their efforts against the Imperial Alliance. After a very long and hard fought battle the Dark forces were compelled to retreat after inflicting heavy casualties on the attacking Space Marines.
Then Grand-Warlord Thorgrim Commander in Chief of the Squat forces fell ill with a Nurgle Plague, he died two days later. The Squat Second-in-Command advocated greater Squat freedom from the Emperor’s troops. In a long and gruelling diplomatic meeting Lord Commandant MacK would not allow a separate Squat command not subordinate to him. Thus although the meeting ended with a non-aggression pact and with a resolution of a few minor details, it was clear that the full military alliance enjoyed by the Allies was now at an end. MacK however after feinting a small scale attack on the city of Trepime a large Space Marine-Titan force smashed an Ork-Chaos force, destroying the Elite Great Gargant Big Donga. The attack saw a daring drop pod attack by the Space Wolves into the heart of the battle. As Eldar mercenaries signalled their withdrawal from the planet, a massive new theatre of operations was opened up for the unprotected territories. The Imperial Alliance, already thinly stretched, was now forced to overextend itself in futile defences that were frequently unsupported and lacked proper organisation. In one week the Imperial and Squat forces were defeated three times at the battles of Optra, Trentine and Stavra. As soon as the reserves became available Lord Commandant MacK launched a massive counterattack and successfully destroyed a Chaos force. Another battle was won by the Space Marines at Lexmark where the Dark Forces were forced to withdraw after a brief and bloody battle. Lacking the reserves to fully exploit the breakthrough, Lord Commandant MacK called up a massive Titan force consisting of a Warlord, a Reaver and Warhounds. The result was a major Imperial defeat at the Battle of Converse, which effectively destroyed the Golden Phoenix Space Marines as the leading military force on the planet.
Then as the Squats came under increasing pressure to take the burden of fighting Chaos the Squat High Command suffered allegations of Chaos corruption. Squat Civil War seemed likely before Lord Longbeard arrived from Forgrell to take control of the Squat counter-Chaos force. He was immediately forced to defend the city of Rugbie, which came under heavy Chaos attacks. The battle ended indecisively. Meanwhile the Chaos offensive now encircled the city of Darel which surrendered the following day, after refusing to allow Imperial or Squat forces to enter the city. With the remnants of Longbeards Squats and whatever troops were available, the Imperial army tried once again to breakthrough. The battle of Cavendish was fought on the two sides of the river Terra, which forced both sides to divide their strength. The result was a narrow Chaos victory and the Imperial city of Trarder was surrounded. With the battle for the old Eldar held territories nearly at an end, Jurghen Slaughterer now renewed his drive for the Imperial capital. The first stage of the operation, the capture of the vitally important Imperial garrison in the city of Citidel, was carried out by Chaos troops supported by Ork units. The battle ended in a stalemate with the Dark forces capturing the city, but losing most of their troops and heavy weaponry. This however gave Lord Commandant MacK his chance and he ordered the Imperator titan down to try and smash through the Chaos forces and relieve the besieged Imperial city at Trarder. Although Annilhator broke through the enemy lines with a bliztkrieg attack, the battle ended indecisively, allowing the city to be relieved and trapping substantial Chaos forces in the city of Gigan. However the Dark forces now clearly held the initiative and being only one push from the Imperial capital the forces of the Emperor looked doomed. The Orks launched their own attack led by their last Mega-Gargant in an effort to link up with the Chaos forces in the East. Field Marshall MacKs response was to send a powerful anti-titan force with one order, destroy the Ork Mega Gargant. This was achieved in the inconclusive battle of Spence, where Kiz Me Butt was destroyed after surviving a suicidal attack from Baron Palanid’s Saxon Knight Household and a Vortex Missile from Vortexo the Warlord Titan. Despite this Kavadah was now surrounded on two sides.
As Lord Commandant MacK designed the defences for the city, he made two risky decisions. Firstly he believed that the Orks would be unlikely to help in the taking of the capital because they wouldn't be able to use their Gargants effectively. This assumption proved correct as Chaos units alone attempted to take the capital. Secondly he chose to create a trench full of water completely around the city and to clear all cover for miles around the city. Fatefully however, he left two bridges intact across the river Terra so as to tempt the Chaos forces to attack in that sector against his strongest and best troops. He was convinced that if the Chaos forces tried to cross the bridges they would not survive in strong enough forces to attempt an attack on the system of bunkers and strongholds held by the Golden Phoenix Veteran and Devastator Companies. Nobody in the Imperial Army had considered what would happen if the Chaos forces used the captured Imperial equipment they had conquered from their massive offensives. Thus when the city was assaulted it came as a shock to find the Chaos forces were using Traitor Artillery companies, and worst of all Super Heavy Imperial Troop Transports. Within five hours the first Greater Daemons were entering Kavadah. The desperate defenders had tried everything including a suicide attack by the Golden Phoenix Veteran Company, which destroyed most of the captured Imperial machines. Despite this and the heroic stand of the Devastator company which destroyed a Leviathan and a Banelord Titan, the Imperial troops were defeated. As a Bloodthirster reached the suburbs of the city, a lone dropship took off from Kavadah space port. Inside were Lord Commandant MacK and the rest of the surviving members of the Imperial High Command, heading to the planet of Crona, totally defeated and dejected. The remaining territories surrendered one by one except Cranium which was evacuated. The Imperator Titan Annilhator was boarded onto a Cargo Hulk along with the rest of the Firebird Titan Legion and flown to Crona, along with the shattered remnants of the Golden Phoenix Space Marines, The Knight Saxon Household and the Cronan Imperial Guard.
In accordance with a secret treaty the Imperial territories in the north allowed their occupation by Squat forces thus securing the vital border fortress of Lucknee XII. Grand-Warlord Longbeard was left in command of the Squat forces as Grugni was flown to Crona for an Imperial Alliance meeting. Gradually the Squat forces were pushed back. After a stalemate with the Orks Longbeard traded land for time and successfully stopped the Ork offensive, but lost the spaceport at Cipe. Realising that they were now cut off, Longbeard chose the spaceport of Trasbortia for a suitable evacuation point. The port was held by Dark Eldar units another unwelcome development. Longbeard’s first attack was direct and resulted in a bloody repulse. His second attempt was more subtle and involved a enveloping attack which was only narrowly defeated. With the Orks and Chaos closing in, the Dark Eldars inexplicably pulled out letting the Squats through. Longbeard was among the last of the SQuat units to leaving the planet thus ending the war for the duration.
MacK on Crona, rebuilt his shattered army and sent an Extermini order on Barooom, but this was refused by the Inquisition who, quite rightly, reminded the Lord Commandant that they alone had the authority to direct such an order. A new Imperial Force under Lord Commandant Morph was sent to retake Barooom and MacK was then temporarily removed from command and court martialled but later cleared of any wrong doing. He was, due to his heroics before the war allowed to maintain his rank and was resent to continue his work on rebuilding the army. The war had changed his outlook on tactics and he took great efforts to rebuild all elements of his army to co-operate more effectively. Alzee remains a Grand-Warlord and is hailed in all Ork territories where his name is used to inspire future Waaghs against the hummies. Jurghen Slaughterer’s whereabouts are unknown. Some say he has joined his master Tzeenitch in the warp, others that he was killed in a Chaos civil war ambush from a rival Chaos Champion, and there is some evidence to support this. However his victory on Barooom was certainly his finest hour.