In Shadowkeep we are introduced to a new faction of Hive. However, I propose or more of speculate that they are actually a pre-existing faction of Hive. Now in D1 on the Moon there were two major factions of Hive, the Blood of Oryx (Purple) and the Hidden Swarm (Red). Now the “new” hive are also red, coincidence I think not! And the similarities don’t stop there.
The Hidden Swarm have one key detail to them that no other Hive faction has been seen with. That being the metal spikes that goes through their arms. This can be seen on Acolytes, Knights, Wizards, and Ogres. And this can be seen on the new hive as well.
Also in footage that we’ve seen of Shadowkeep the acolytes and the knights of the Hive appear to have the same appearance as in D1. As for the new wizards, while we don’t see much of them in the reveal from what I could make out they appear to be an updated model but still very similar to the D1 appearance. The new thrall also have similar if not matching red markings on their shoulders as well.
This would also make in-universe and narrative sense as one we hear nothing about Savathun’s hive appearing on the Moon and I don’t think the Hive have instantaneous travel between one planet to another. And two since we kind’ve abandoned the Moon it can be assumed that the Hive their were allowed to just do what they wanted. So the Hive in Shadowkeep are simply just the Hidden Swarm.