Octarius War
The Octarius War is the most hilarious and fail venture the Imperium of Man has ever made. And believe us, that is no small feat.
The Imperial Guard were having their asses handed to them by the Orks on the planet Ghorala in the Octarius system. Former Lord Inquisitor Kryptman, leading expert on the Tyranids and prolific bastard, decided that the best solution would be to sic a recently captured swarm of Tyranids on the Orks, let the two fight it out, and mop up the remaining survivors with the IG. The obvious flaw in his plan of course is that both Nids and Orks thrive on war, being unintentional experts at biological warfare, meaning the survivor would emerge much stronger than ever before, though hopefully if the Tyranids win they will be over-specialized ork killers and be weak to other threats and fighting styles. The conflict has currently devolved into a massive meat grinder, where neither side has a clear sight of winning, and both races are fucking loving it.
This tale is notable for being one of the few bits of fluff in the Nid 'dex where they don't get their arses handed to them by space communists, space elves, or fucking smurfs
Never mind on the Eldar part, they're currently trying to clean up Kryptman's mess by bio-purging the front line and worlds around it. Unfortunately, they missed the Overfiend of Octarius, who just managed to loot an Avatar of Khaine...fucccckkkkk.
Oh, and Ghazghkull himself is on his way there too so he can call up more boyz for Da Great WAAAAGH!!!! Score one for the Orks, it looks like. After arriving there and killing a mawloc from the inside out (eat youheart Alien), he managed to take over the leadership of the octarian orks.
With so much carnage and destruction going on, it was bound to attract the attention of the ruinous powers. In particular, a Khornate warband called the Skullhunt of Vodha Bloodprice attack the system, declaring a Blood Crusade. And their results are... mediocre, to say the least. In the CSM 8th ed. Codex, it says the khornates were able to get "over eight thousand skulls are offered to the Blood God, the smallest of which is the size of a boulder" and that was enough to make Vodha Bloodprice ascend to Daemonhood. Which sounds too weak to be true. Sure, skulls the size of boulders are nice and all, but considering the amount of orks and tyranids are around Octarius, just 8,000 skulls is too damn little. We can get that amount of deaths by a relatively safe trip to the Warp, or a very succesful imperial guard campaign. But khornates fighting orks and tyranids, two of the most bloodthirsty and warmongering species in the galaxy, not to mention numerous, and all confined on a single planet? It just screams lazy. Khorne must be becoming old if he grants daemonhood for such a half-assed job. Anyway, the Blood Crusade probably had to retreat fast due to the massive opposition and being sandwitched by the orks and nids, and the fact that the Indomitus Crusade started, so there were fresher pastures to drown in blood.