"In peace, sons bury their fathers. In war, fathers bury their sons."
The War Rhinos are a 21st (Cursed) Founding Chapter of Space Marines founded to combat the Tyranid Hive Fleet Tarrasque, which was in the process of invading the Presidium Sector.
The Chapter has a genetic mutation, as do most 21st founding Chapters, that manifests as extremely tough and leathery skin, making each Astartes in the Chapter remarkably hard to kill, even in comparison to other Space Marines.
The War Rhinos were founded to combat the tendril of Hive Fleet Tarrasque invading the Presidium Sector. In the initial encounter, the Chapter took heavy losses, the entire 10th company being devoured by the Hive Fleet's abnormally high amount of monstrous creatures, Carnifexes in particular.
By the time the second engagement came around, the War Rhinos made planetfall via drop pod, half of the Chapter landing behind the swarm, and the other half engaging directly from the front. The half that took the rear was comprised of the 6th, 7th, 8th and 9th Assault Companies, while the front was held by the 1st-5th Companies. In the end, the Hive Tyrant leading the swarm was slain, and the Hive Fleet retreated to their ships. While the War Rhinos were celebrated for their victory, all Companies excluding the 1st and 7th had been devoured by the Tyranids.
Shortly thereafter, a Deathwatch Kill-Team led by Captain Orion of the Marines Errant boarded the Hive-Ships, and poisoned the spawning pools with their specially made toxin, destroying this tendril of Tarrasque.
The War Rhinos' Homeworld, Thrace, is a 'graveyard of ships', a collection of ancient space hulks and asteroid chunks left drifting in the aftermath of Hive Fleet Tarrasque's invasion. The various space hulks come in different shapes and sizes, but all are Imperial made. It is common for genestealers to be encountered on some of the outer ships, their spawning vat yet to be located.
The War Rhinos culture is undeniably unique. In terms of physical features, the Astartes all appear most similar to Terrans from the area that was once Germany. Sleek blonde or black hair, and brown or blue eyes. In terms of customs, the Chapter is perhaps most questionable in their belief system. Once an apothecary harvest the progenoids from a fallen Astartes, that Astartes is then to be preserved and sent back to his homeworld, where his parents may give him a proper burial. However, due to the majority of the Chapter being consumed for biomass by the Tyranids, no Astartes were transported back to their homeworlds after death. In such a case, it is customary for a letter containing the names of all the fallen battle-brothers to be distributed to the various homeworlds.
Presidium Campaign: The Presidium campaign was a grouping of engagements between the War Rhinos, the 182nd Presidian Imperial Guard, and later the Deathwatch, against a tendril of Hive Fleet Tarrasque. The campaign was fought on 5 worlds, and the casualties were grievous for both sides, the War Rhinos losing over 80% of their Chapter in the final assault. The campaign ended with the Hiveship's destruction at the hands of the Deathwatch kill-team led by Watch-Captain Arinal of the Howling Griffons.
In terms of belief, the War Rhinos are not a particularly religious Chapter, preferring the old Imperial Truth over blind belief in the Lactitio Divinitatum. This, in addition to their mutation, has earned them the watchful eye of the Inquisition's Ordo Hereticus, ready to expunge the Chapter at the first sign of heresy.
Seeing the Inquisition as little more than oppressors and crazed zealots, the War Rhinos ignore their existence altogether, keeping to themselves.
Chapter Master Alaric Armand - Chapter Master Alaric Armand of the War Rhinos is a paragon of the beliefs of his Chapter. Strength and raw power is the only thing capable of defeating the enemies of Mankind. Towering over the other members of his chapter in modified relic Cataphractii-Pattern terminator armour, he leads his Chapter from the front lines, Thunder Hammer in one hand, Chainfist in the other. Rarely is he seen away from his honour guards, the Blackhorns, also in Cataphractii-pattern armour wielding Chainfists and Storm Bolters.
The Chapter seems to have offended the Adeptus Mechanicus at some point in their history, resulting in them receiving very little in terms of armour. Due to this, they are mainly seen wearing Mk 4 and 5 Power Armour, with only the highest among them (The Chapter Master and Honour Guard) wearing Mk 6-7.
The War Rhinos wear the colours of steel and a darker grey primarily, with the trim of their shoulder pads being brown. These colours reflect both the outward appearance of a Rhinoceros, and the Chapter's propensity to not keep their armour in the best of condition.