The Svolochi are a Chapter of Space Marines located on the Hive World of Kenzeldenerii, located in the outer region of the Segmentum Obscurus. They are a chapter known for being equal parts suspicious, mysterious and paranoid as well as have a very difficult relationship with the rest of the Imperium of Man, especially the Inquisition and other Space Marine Chapters. Despite there always having been suspicion of them being aligned with the Dark Gods, they do claim to have fierce opposition to it, and have demonstrated it many times, yet this has not stopped others from casting judgements, however, most of which are justified.
The home planet of the Svololchi is a hive planet that is roughly four time the size of Jupiter. On average, the days are longer than the average Terran day, and the temperature is roughly the same. Due the larger gravity, the structures built on the planet's surface are so architecturally sound that not even Daemonfire could melt it.
On top of the planet itself, Kenzeldenerii also has many moons, upwards of sixty. Most are feral worlds and are almost unable to support any form of life, but there are some that have been occupied, the most important are Zingel, Taurad, Instard and Sitzel, which are all forge worlds. The other hospitable planets are farming worlds, and training worlds for the Svolochi.
The origins of the Svolochi are completely unknown to imperial records. Even with the deepest of research, not a single trace of the chapter's origin could be found. Not even a founding number or founding chapter. The current master of war, Beziid Genjeb, believes that the chapter must be old, as they themselves cannot remember their founding nor their founding chapter.
It's hypothesized that the chapter was assigned to protect Kenzeldenerii , as it is a key tactical point for the Segmentum Obscurus. Having it overrun by chaos would thus mean providing the forces of the Dark gods with four whole forge worlds. Over time, the inquisition realised that they had put a space marine chapter with no known founding or gene seed in charge of a hive world and four forge worlds. This meant that there was a large and quite scary possibility that, if they turned out to be a chapter with a corrupted gene seed lineage, they would not only have a large source of recruits, but also a ready source of arms.
This possibly cataclysmic outcome led the inquisition to investigate the chapter. What they found did naught but encourage the inquisition's suspicions. They found that in the past, the chief librarian challenged the then master of war to an all stakes fight to the death on the moon of Estengalor for the position of master of war, as he was tired of only being in the position of chief librarian. He was considered the most powerful psyker in the chapter's history and felt that being the chief librarian was too below him. He was defeated, and when he died, a warp portal opened up, and from it spewed thousands of pink horrors. The result left the chapter master killed, and the moon had to be purged of all life.
This event caught the attention of the forces of chaos, and soon, the shrikes, a Tzeentchian chaos space marine warband, arrived. In order to turn the imperium against the Svolochi and effectively fight the battle for them, they painted their armour in the same colour scheme.
The inquisition's investigation concluded that they were heretics and ordered an extermination of the chapter with many astartes chapters invading Kenzeldenerii to wipe them out. Now, the Svolochi had to fight off both the forces of chaos and the forces that were supposed to be their allies.
In a last ditch attempt to end the unnecessary bloodshed, the master of war, Benziid Genjeb spoke with the lord inquisitor in order to convince the inquisition that they were not heretics. He admitted that the chapter's history was checkered at best but said that they were above all pure and faithful to the emperor.
The inquisitor was skeptical at first, but conceded, eventually. The chapter was granted the emperor's pardon, but was forced to have their numbers reduced to 200 marines and be forced to defend their home planet for two hundred years without help of any Imperial sect, aside from one of their forge worlds, and without the ability to recruit more neophytes.