Though acting independently, the Warlords were known to still use the Galactic Empire emblem
The Imperial Warlords are a minor faction in Thrawn's Revenge but serve as major antagonists to the players chosen faction (often as the New Republic and/or Imperial Remnant) in several of the GC scenarios, such as The Hunt for Zsinj and Reunification. Though ingame the Warlords are a united faction, they're in actual fact very hostile towards each other in canon and certain Warlord hero units can be found on certain planets indicating that there are branches within the overall ingame faction.
Beginnings
Battle of Endor
It was during the battle of Endor where the first Imperial Warlord and its faction was created. The battle turned in favor of the Rebellion when the Imperial flagship Executor was destroyed. It didn't help that Emperor Palpatine, Darth Vader, and the second Death Star itself were all destroyed soon after. In the fleet hierarchy, the Imperial II-class Star Destroyer Chimaera under the command of Admiral Horst Strage was designated third-in-command of the fleet defending the Death Star, it quickly became the lead ship after the Executors and another Battlecruiser's demise. However Admiral Strage was killed, leaving his subordinate, Captain Gilad Pellaeon, command of the Chimaera.
Commander of the Star Destroyer Whirlwind, Admiral Blitzer Harrsk however, refused to take orders from a mere bridge captain with age-old distinctions, and departed the Endor System and the battle altogether with several other ships whose captains also agreed with Harrsk. He took his new-found followers to the Deep Core and refused to take orders until a proper chain of command had been established.
Further establishments
Another Imperial who soon abandoned the Empire was Grand Moff Ardus Kaine. Although the news of the Emperors death spread quickly, by the time Kaine discovered this it was about a week after battle concluded. Though officially and truly loyal to Palpatine since he was a senator, even a man like Kaine would have ambitions that needed something like Palpatine's death to become a reality, and thus he made the Pentastar Alignment. Others who did likewise were High Admiral Treuten Teradoc, Admiral Zsinj and Sander Delvardus, each creating their own little 'kingdoms' in the sectors they were stationed at. The Galactic Empire was falling apart.
Factions
Each Warlord would often give their Imperial 'Kingdom' a name to help establish and legitimize themselves. Known factions included:
Zero Command - headed by self-styled High Lord Admiral Blitzer Harrsk, located in the Deep Core.
Pentastar Alignment - Headed by Grand Moff Ardus Kaine, stationed in Oversector Outer at the Galactic north of the galaxy.
Greater Maldrood - Headed by High Admiral Treuten Teradoc, station in the Maldrood sector in the Mid Rim.
Federated Teradoc Union - Headed by Kosh Teradoc and later both him and his brother Treuten, located within the Deep Core.They are the forces of Kosh and later the Greater Maldrood combine.
Eriadu Authority - Headed by self-styled Superior General Sander Delvardus, taking dominance of space around his homeworld of Eriadu and the Rimma Trade Rout, one of the smaller factions.
Zsinj's Empire - While not having an official name, this faction was headed by legitimate Warlord Zsinj stationed in the Quelii Oversector with Dathomir as his Capital.
Imperial Civil War
Each and every one of the Imperial Warlords believed that their way of thinking was correct and all other judgment was incorrect. This lead to minor skirmishes or team-ups with other faction, while others erupted a full scale war with other parties. In 5ABY-9ABY, the majority of the Warlords just kept to themselves defending their own holdings. Skirmishes were common with empires whose borders were close to other empires, that such of Zsinj's Empire and the Greater Maldrood, causing bitter rivalry between Zsinj and Treuten until the former's demise.
There were some within the Galactic Empire who sought to re-unite the fractured Empire, the first being Madam Director Ysanne Isard, head of Imperial Intelligence and future Empress of here 'Supreme Empire'. While Warlords like Harrsk kept good relations with Isard and the Empire Proper, it was only when Isard lost control of Coruscant to the New Republic and became an Independent Warlord herself that she lost the trust of many fleet commanders, causing more Imperials to abandon the mainstream Empire. She was eventually defeated by Wedge Antilles and Rogue Squadron.
With the New Republic beating down the dying Empire, both factions began to realize that they had a common enemy in the shape of Zsinj. The Empire had a strong hatred towards Warlordism and by this time Zsinj had already thwarted two attacks on him by the New Republic, both parties agreed to a truce in 7ABY to bring down Zsinj. Zsinj was killed over Dathomir by General Han Solo with the aid of the Hapes Consortium. With this, the truce ended which caused the Empire, New Republic, and the Greater Maldrood all gunning it to capture as much as Zsinj's territory as possible. The victor being the NR, and the loser being the Maldrood, causing Treuten himself to retreat to the Deep core and join forces with his brother Kosh.
Eventually upon hearing about Palpatine's death and the Empire's fragmentation, Grand Admiral Thrawn took control of the Empire. Simply by reputation alone he was able to unite several Warlords; Teradoc and Harrsk however were not among them, preferring to keep to their holdings. Thrawn even offered Moff Kaine of the Pentastar Alignment to join him, though Kaine declined, but kept it under consideration. Thrawn's progress was good, the Empire proper was able to recapture at least a third of its territory back. However, the Empire would again be in reverse after Thrawn's demise at Bilbringi, interestingly enough though; it was only just before the Battle of Bilbringi that Moff Kaine decided to aid Thrawn's fight and was preparing his forces for battle, with Kaine himself preparing to meet Thrawn at Bilbringi. He quickly learned of his demise and kept his military at bay. It was only a few months afterwards where the Imperial Civil War would pause.
Palpatine Reborn and the Dark Empire
The Warlords eventually put their private wars aside and as a united force, set their sights of Coruscant. The battle ended in a quick and overwhelming victory for the United Warlords. But old habits die hard, internal squabbling took place and the Imperial Civil War erupted again above and on the surface of Coruscant with most of the planet being leveled via heavy-walker-warfare or by orbital bombardment. This led to the NR driving the Warlords off Coruscant. It was then where the Dark Empire emerged, with Palpatine in a clone body at its head. This time Kaine, Harrsk, Teradoc, and all other factions united and made a successful campaign against the NR.
It was all going well for the Empire, but it soon started to fail. Palpatine was killed again when he lost control of a Force Storm he unleashed to destroy an NR fleet. His clone bodies were tampered with to have a shorter life span which would ultimately be his downfall as he was unable to move his consciousness to newborn Anakin Solo in time, resulting in his final and permanent death. And it was this fate that was also bestowed upon the Empire.
Splintering again
Now self-styled Supreme Warlord, Blitzer Harrsk returned to his fortress world and resumed leadership of Zero Command. Treuten's left over forces from the Greater Maldrood were beaten upon badly, being left with only 72 Crimson Command ships left to hold to his name while Kosh resumed primary leadership of the Federated Teradoc Union. Superior General Sander Delvardus lost all his holdings around Eriadu and in the Outer Rim, he eventually settled on a desert world in the Deep Core with his second-in-command Colonel Ivan Cronos.
The Imperial Civil War resumed with Harrsk and T. Teradoc being the bigger and more noticeable combatants. It was at this time that the Empire was well and truly dead.
Reunification
After her failed campaign against the NR, Imperial Admiral Natasi Daala focused her efforts on re-uniting the Empire, or rather what was left of it. While she went to personally visit Harrsk at his Fortress world, her chief aide, Commander Kratas, went to inspect the Warlords flagship, the Shockwave. It was an ill-timed visit; T. Teradoc learned of Daalas visit and sought to humiliate Harrsk by ambushing his Fortress. The Attack resulted in a victory for T. Teradoc with the Shockwave destroyed, Kratas dead, and three other of Harrsk's Star Destroyers damaged. This did not please Harrsk nor Daala, resulting in a quick retaliation strike with Daala being forced to lead from the Firestorm. Harrsk refused Daala time to plan as he wanted the element of surprise to be his main weapon.
The Battle of Teradoc's Fortress resulted in a cease-fire between the two Warlords when Daala threatened to kill both of them via self destruct. T. Teradoc's second-in-command, Vice-Admiral Gilad Pellaeon agreed with Daala's views and was quick to team up with her. Together they organized a meeting between the 13 Deep Core Warlords.
They all arrived at the meeting place of Tsoss Beacon. Each Warlord were told to keep their fleets at bay away from the system too which all of them did. As Daala pitched her ideas of unification to the Warlords, Harrsk and T.Teradoc mocked the proceedings. Sander Delvardus eventually decided that the talks were a waste of time and attempted to walk out but Daala sealed the door closed to prevent anyone leaving. It was an other 3 hours until Daala had finally come to terms that the Warlords were never going to come to an agreement. She and Pellaeon equipped themselves with gas masks and released nerve gas into the room. With desperation, the Warlords tried to escape throughout the door but to no avail as it was still sealed. The gas eventually caused all the Deep Core Warlords to die and Daala to gain access to their various forces. She received the services of Colonel Ivan Cronos and the Teradoc's Crimson Command VSDs from the Maldrood, for instance.
In Game: 2.15
in game, all the warlords work together. in progressive GCs like Art of War or Imperial civil war, they have a group of planets around Dathomir, the Corporate sector, and surrounding territory. with 2.15, the warlords will build units, attack and conquer planets, and act like a normal faction with 2 major exceptions: First; they are unaffected by era changes, and Second; they are not playable. they can build basic Imperial units, and have a SSD hero, Zsinj. because of location, they will most likely cause the most trouble to the Pentastar Alignment and the New Republic. if you play as those factions, be prepared to have a fleet to deal with them quickly and early on, before Zsinj gets loose.
In Game: 2.2 and Beyond
With 2.2, the warlords will no longer co-operate with each other. with Zsinj(Zsinj's empire), Truetan and Kosh Teradoc(Greater Maldrood), and Sander Delvardus(Eriadu Authority) as playable factions, the rest of the Warlords are independent as well. 6 have been confirmed to date: Blitzer Harrsk's Zero Command, Corporate Sector Authority, Prentioch Dominion, Elrood Sector, Ciutric Hegemony, and Moff Tol Getelles Antemeridian Sector.