Editing Nobledark Imperium Notes (section)

= Tyranids =

The tyranid "strategy", if you can call it that, is to sweep through the galaxy from the galactic southeast (generally where they're making galaxyfall) towards the two biggest points of psychic energy in the galaxy. Which would be the Astronomican and the Eye of Terror. The specific path they are following is one left by the genestealer cults during the Genestealer Wars in late M36. When the Imperium noticed the path of the tyranids seemed to be following the path of the old genestealer cults, they traced the trail all the way back to the Segmentum Solar.

Battle of Ultramar wasn't with Behemoth in this timeline (or at least, the battle of Ultramar everyone thinks of), it was with the advance forces of the main tyranid Hive Fleet, about 200-300 years before galaxyfall. This is the time when the Swarmlord first starts showing up in tyranid fleets.

Leviathan's weird movement to approach the galaxy from below the galactic plane is a result of swerving around to try to avoid the Outsider's Dyson Sphere. This unusual movement is how the Inquisition learned such an object existed in the first place.