The warband came to be after the disillusionment of a Primaris Intercessor marine, who after seeing their looses on their campaign to liberate the Archmund System, decided to join the foe he was battling, as he saw that the ways of Chaos would benefit the Imperium if used wisely. As such he joined the Death Guard, taking over the warband he was inhabiting (previously called "The Three Lobed Skull") in order to leader it on what he believed would be a greater path.
They are mostly from the First Founding Legions, the Death Guard, previously known as The Dusk Raiders. Their leader Raynor Mortus comes from the Ultramarines Chapter, Castellans of the Rift, having defected after seeing the power, strength, numbers and durability the Barbaran astartes possessed.
- The fall of the Castellans: This is the point were the Three Lobed Eye transitioned into what it is now, the battle occurred in the reaches of space, the main flagship of Mortus's previous chapter was boarded, the Plague Marines overwhelmed the loyalists and ended the lives of many, taking all the slaves they could. Mortus himself killed the Chapter Master, thus securing a duel with their Chaos Lord, who sought the leader's head for himself.
- The Seventh Skull Harvest: The Ursi began to search for any available information on the gatherings of the newest Skull Harvest, apparently held in memorial for the success of the 13th Black Crusade, three warbands made it, the Bears, The Crimson Wolves and the Perfect Blades (World Eaters warband and a renegade Imperial Fist chapter). On each battle Armund and Mortus battled the enemy, finally ending on a the three Chaos Lords dueling to the death on a massive arena, thanks to his superior durability to both he outlasted his foes, taking their skulls for the Blood Reaver, promising him that he would bring a greater slaughter with the forces he obtained.
- The Kerberos Purge: Armund sets his sights on the planet of Pluto, desiring to destroy the orbital defenses of one of his heavily fortified moons, desiring to see if they could cripple Terran communications, during their battle they saw the infamous Purge warband, attempting to destroy all life of the planet, both warbands battled on equal sides, ending the defenses and might Kerberos possessed. After the skirmish, the Bears began to take slaves and possible recruits, before they realized that the Purge was killng indiscriminately. Both forces came to blows before leaving. noting that the Purge warband was undeserved of Nurgle's favor.
- The Siege of Talruldis: The Talruldis system was besieged by a great many incurable plagues, many cultists of the apocalypse began to be created and it seemed like all hope was lost, this was indeed the work of the Bears. Their experimental plague asteroids, containing carefully contained infections and disease works into a container, inside a nearby stone of the void. The system's downfall was considered a success as the ax heads began to fall on each world, conquered by the marines and the populations own, desperate infighting.
Raynor Mortus, the Plague Primaris
(For more info) The Chaos Lord and main source of beliefs. He is a Primaris marine, a defect of the Castellans of the Rift, he ended the life of the Chapter Master of his original warband alongside the Lord of The Three Lobed Skull, for his offerings and these deeds he obtained a Mark of Nurgle that gave him the ascension to Lordship of his warband.
Armund the Faithful
Sorcerer and second in command. He was less than impressed at the petty piracy of his fellows, the lack of faith and ambition beyond backstabbing, desiring to fight the Imperium with the same zeal and righteousness of the Black Legion, Word Bearers, and Red Corsairs. Mortus was a insight into that opportunity, taking him as his protegee from the day they first telepathically spoke.
He is the most powerful psyker on the warband as of now, capable of summoning daemons with only the accumulated despair of the foe, or a very small number of human sacrifices, a master in creating plague, infiltration agents, Armund is a foe to be reckoned.
Armund is a fervent fanatic, anyone who defies the tenants of divinity is seen with contempt, ignored and demonized (well, as much as a Traitor Astartes could be). The following Legions and warbands are those that the Ursi show most unwillingness to aid, unite or convert:
- Night Lords: Seeing them as hypocritical, self righteous sadists who rarely, if ever unify into combating the Imperium, mostly running and doing petty raids on survival's name. The fact that most (bar Krieg Acerbus's own warband) are faithless, this is a recurring theme with the Lord of the Bears, those unwilling to cooperate with Chaos are cast aside.
- Alpha Legion: Similarly they see them as cowards for their indirect, misdirection tactics, believing that most of them are similarly agnostic/maltheistic, he ignores them more often than not, only attacking if provoked (which could count to even Legions he respects).
- Ahriman's Thousand Sons: Unlike a few Plague Cultists, both Armund and Raynor are indifferent to the worship of Tzeentch, seeing their battles against them as expensive wastes of time and more often than not seeking compromise. But Ahriman and his lot seem to be a kin that both despise, like both the sons of Curze, and the hydra they are apathetic on the ways of worship; Even worse, believing the Gods of Chaos to be the opposite of sapient and sentient, and believing they can control their own destiny and will.
- Emperor's Children: They see the Children as the stereotype of the common, low and mentally diseased Slannesh worshipers. Their faith being always selfish, indeed the God/dess or pleasure was never liked by the Warband's leaders, seeing them as preening, superficial wretches unable to properly unite beyond a future backstab. As such they ignore or even fight if necessary.
- The Purge: They, on the mind of many in the warband are the exact opposite in beliefs to what they preach. The Purge only wish to destroy, not unite nor give a worthwhile future, only genocidal desolation, no different to what many believe the Necron's goals are. As such of all the warbands they are one of the few that they constantly fight if meet.
Those that the warband is willing to both faith at their side and have reluctance to strike are the most "popular" Legions on the Eye, those who are either a semi-unified force or at least making a noticeable attempt at the rooting edifice that is the Imperium:
- Black Legion: The Black Legion is all but admired by both Armund and his Lord, noticed for breaking the Imperium in half (and, unintentionally creating the troubles Mortus had to go through) alongside their seal, righteousness of their deeds and high value for brotherhood, indeed those ideals are almost romanticized by the warband, and considered a great example of Chaos Space Marines. Armund has personally meet the Despoiler, as he requested the help of warbands of World Eaters, Thousand Sons and Death Guard, the Nurglite bowing before him in respect of his goals and mindset in archiving them.
- Word Bearers: They are seen equally as great as the Imperium's Demise. Their faith and persistent attacks on humanity a aspect that nearly all Marines should inspire themselves. Some of their battles have been alongside the sons of the Aurelian, making them a ally to be tolerated and respected.
- Iron Warriors: Even thought the sons of Perturabo are faithless Armund admires them for their reason of turning, seeing themselves as unrecognized workers, only pigeonholed to do the dirty works of the crusade, being worked to exhaustion alongside disrespect, turning when the First Warmaster saw their worth, unlike the Emperor. Their ideals of endurance, almost darwinian mindset, stoic, no-nonsense behavior makes them allies or at least inspires tolerance on the Bears, the Warriors themselves are mostly disgusted by their admiration but their willingness to ally is at least recognized.
- Red Corsairs: The ambition, and the reason of their turning from the Imperium are cautionary tales of believing in such a decadent, rooting edifice. As such the Blood Reaver's warband is welcomed to be allied if necessary, it is believed that after the creation of the Rift, Huron created his most recent Skull Harvest, the seventh. At such a opportunity the Bears took it, Armund succeeding on the last three way battle, taking a price of a thousand slaves, and two warbands, which swelled his number far more than he could expect.
Cult and culture
The Ursi are characterized as a violent, frontal warband on terms of ground combat, utterly ruthless and unrelenting, Raynor's power aspires them to go to the offensive more often than not, which benefits of their enhanced durability. One of the recurrent characteristics is the usage of chemical weapons no dissimilar from Destroyer Marines or the Death Guard's own Grave Warden. As some of the resources are scarce, recreations of these chemical weapons are often of Nurgle's devices or sorcery. These troops of blight are often on the forefront, and are terror units or shock troopers.
The Plague Seeds
One of the main tactics of the Bears is to introduce a hidden contagion on a world or system, sending these to primitive planets first, as this happens the defenses weaken as the contagions spread at a accelerated rate, after a month of waiting the fortifications fail, the marines descend upon the planet, already softened by daemons and the moribund infected, praying for Nurgle, and ripe for the reaping. This is called a crude way of infiltration and sabotage, as it weakens the foe, crushing their hopes into dust before the axe head falls.
They take any human of teen age available, they are subjected into indoctrination and hatred of the Imperium. On occasion they are willing to accept fellow Nurglite warbands or convert some via plagues, before capturing them and using the biological and sorcerous tools to break their spirits, showing their distorted perspective of the Imperium.
The Ursi Securis is a attempt of their warlord to recreate and reintroduce the original beliefs of the Dusk Raiders; This was that humanity should be free of the oppressors, with open defiance, determination and faith in inner strength, this ideal became less used, degenerating the Death Guard into elitists that had contempt for the weak and the non-combatant. Mortus's idealized view of both Chaos and their Barbaran roots gave him the faith to make these ideals again into the fore.
Nurgle could be seen as a liberator, the one who will aid the destruction of the greatest oppressor mankind has faced, the Emperor and his Imperium, as such they are apologists that will do anything to gain a foothold on the Long War. Believing that they are liberating the race of man, fortifying them with the strength of Chaos.
They are a fleet based Warband, but on some important councils by Mortation, it is known that the Bears go to the Plague Planet, sometimes taking daemons or plague beastmen for serfs and slaves.