Jericho Reach

The Jericho Reach is a region of space in The Ultima Segmentum, and the setting for the Deathwatch Role-Playing Game. It also has a metric fuckload of xenos, heretics, and other assorted nasties. The Imperium is currently fighting the Achilus Crusade to make the Xenos, Heretics, and Xenos Heretics GTFO. It's also about to be conquered by the Tau, if the Tyranids don't stop over for dinner first. In short, The Forces of Chaos, The Imperium, the Tau, and the Tyranids of Hive Fleet Dagon are about to have the greatest showdown the galaxy has ever seen... If GW and/or FFG would unfuck themselves and advance the storyline (which they kind of did, but in a way that made the whole thing a moot point.)

History

The story of the unending, sector-wide Verdun that is the Jericho Reach started during the Great Crusade, where it, after a long and bloody campaign, was reforged into shining example of Mankind's dominion. It was verdant, prosperous, and strategically located near The Eastern Fringe. After The Horus Heresy, not much changed, except for one thing. The Deathwatch, formed after the war against The Beast, decided to plonk themselves down there and set up camp, watching for signs of xenos activity from The Eastern Fringe. The Iron Lords guard the Grendl Stars here in the Hadex Anomaly.

Eventually, Anarchy descended over the Jericho Sector, with entire worlds turning to chaos and madness. This coincided with The Age of Apostasy, so response was limited. Meanwhile, Chaos Cultists were shitting themselves with excitement due to a prophecy that was about to happen. In 656.M40, a prophecized planetary alignment buttfucked a hole in reality, right in the economic capital of the Jericho Sector. Think if a gargantuan, reality breaking tornado just exploded into being in the middle of London, and then daemons started rampaging over the beautiful english countryside, slaughtering/infecting/burning/raping all over the UK. Now supersize every location into the size of a solar system.

Yeah, the already wartorn Jericho Sector went completely FUBAR, and though the Deathwatch kept watch and all the death happening in the sector, they never intervened, following some secret prerogative only they knew of. Many of the supplements talk about how that most of the stations were largely automated and only had skeleton crews. With shit going to fuck faster than they can even get wind of it, most decided to go into sleep mode and wait until the whole thing blows over. In 755.M41, The Imperium arrived through the rediscovered Jericho-Maw Warp Gate, a giant, ancient, webway-like structure connecting the Calixis Sector and the Jericho Reach, and plans were made to restore order. Meanwhile, the Tau continued to expand into the Jericho Sector, their first known appearance being in 400.M41. In 812.M41, The Shadow Of The Warp descended on The Jericho Reach, disrupting communications for The Achilus Crusade. Soon after, two Tyranid Ships are detected.

Following the theme of mankind's biggest enemy being itself, a lot of the struggles involve conflicting goals: the leader of the crusade has a raging murderboner for the Tau, at the point of always ordering the attack even when there is no strategic capability or benefit of doing so. As Tyranids start to encroach, and the taint of chaos and rebellion fuck up the territory that is held he continued to double-down against the Tau, to the point of becoming increasingly belligerent to everyone who disagreed with him. The Tau, for their effort, are trying to exploit is atavistic paranoia to their benefit by having neutral planets come to their side.

Major Nonhuman Species

• The Tau Empire is the major xenos threat Better Alternative *BLAM* The Emperor of Mankind is the Divine Sovereign of all humans! To betray him is "HERESY!" in the Jericho Sector. As well as the Tau, they also employ large amounts of Kroot Mercenaries and Vespid Stingwings, as well as smaller amounts of Demiurg and Reptilian Mercenaries called Tallerians.
• The Tyranid Hive Fleet known as Dagon appears to be making a beeline right for the heart of the fightan. Fortunately, they will never get there, as time appears to have stopped at 999.M41 Not anymore. Fear, for the shadow in the Warp comes.
• Various Daemons come pouring out of the Hadex Anomaly, as is the norm around warp anomalies.

Minor Nonhuman Species

• Enslavers, especially in the parts near the Hadex Anomaly.
• Khrave, members of a large, mind-eating race of xenos. I could make a lame pun here, but I won't. Khrave have been confirmed to resemble furry, insectile humanoids, with faces like bats. It also seems that they can vary in size and whether or not they have wings.
• Lacrymoles, shape shifting xenos often used as assassins, their default appearance is said to be an evershifting mass of flesh with only glowing red eyes remaining stationary in the middle of their body, but they also have been seen as chitinous white skinned humanoids with compound eyes and mandibles, as shapeshifters though they could likely be either fairly comfortably. The Deathwatch has fought these dudes on multiple occasions, and it is possible that a shape shifting assassin who killed a bunch of deathwatch and two inquisitors during The Feast of The Emperor's Ascension in 756.M41 was also one.
• Loxatl, large, sapient, grey lizards who smell like that guy's armpits after a 10 mile march.
• Eldar of all types (Craftworlder, Dark Eldar, and Harlequins), working together here to try and get the jump on...
• ...the local Necron dynasty, led by a Phaeron who was unhinged long before his awakening drove him completely mad.

In short, everything is horrible, and has been for the past ~4,000 years, and that's before you remember the Hadex Anomaly became one of the endpoints of the Cicatrix Maledictum. Have fun.