Ullanor!!

[miteyheroes]

There's some good info on Ullanor in the new Fear To Tread book.

The main fighting at Ullanor was the Emperor leading the Guard & Titans in a massed steam-roller fight against the orks whilst Horus led the Luna Wolves strike force that killed the actual warlord. I think the other Astartes were fighting on other worlds against the same waaagh, not Ullanor itself? Afterward the death of the Warlord, the waaagh broke up into in-fighting.

Then there was the Triumph, where Horus was made Warmaster and the Emperor retired.

After that various Imperial forces wiped out the remaining orks from the Waaagh - notably the White Scars in the Chondax System (where the Alpha Legion intentionally kept the White Scars bogged down, as briefly shown in the Alpha Legion story in The Primarchs anthology). Of course, orks being orks you can never completely defeat them, but that's their last major part in the Great Crusade/Horus Heresy (although the Ultramarines thought Calth was going to be a muster before attacking orks...)

[-Tom-]

That taken into account, why didn't they just push on from there and finish the Crusade? Galaxy would've been safe in no time surely?

The Horus Heresy books kick off after Ullanor, and give mention to it briefly, but only really covering what is already mentioned in the thread. By the point of the books, the chapters have gone off in their own directions continuing the crusade. However I think the point to bear in mind is that space is a BIG place. At Ullanor there was a really big enemy all crammed into one place, so they needed plenty of marines/terrans to fight them, in that same one place. There's no point then continuing onto the next planet to be subjugated with that same massive force, if that planet only has 12 alien dairy farmers on it, better to split up the forces to spread in multiple directions, (which is what they did).