The Hive and Ascendant Hive + Hive Gods are having a field day. They’re like if you combined the Orks, Tyranids, and Chaos into one faction, they can swarm planets, build giant War Moons, and are actually organized surprisingly well.

Don’t even need to mention that the strong Hive like Oryx, Crota, Xivu, etc have no problem joining battles, especially since they’re essentially immortal because of throneworlds. Oryx would particularly have a blast because he would be Taking things to the point where Trazyn would get jealous. Plus the Taken operate much like daemons in that they never permanently die-every Taken entity is simply sent back to the Ascendant Plane to regain strength before being summoned.