jbox1
It's complicated but basically they're AI called MINDS that when fully powered, and in a suitable HIVE (The shells that contain them) are capable of corrupting all technology. The HIVES are capable of creating a lifeform called the Storm, that worship the HIVEMINDS, if their lifeblood comes into contact with any form of biological life. These HIVEMINDS compete over territory with little regard for any race that doesn't provoke them. They're essentially Lovecraftian gods. If you were to come into contact with the MIND then you would go insane take for example the ironclad soldier who's chip was corrupted by ANUBIS. He was able to see the HIVEMIND ANUBIS as he truly is and his goals. However it was too much for his mind to understand. The data centers are a way to access the plane of existance that MINDS inhibit if they are without a HIVE. If a data center is corrupted by ANUBIS then it is shut off for anyone to enter except his Storm. As well any other MINDS in the area that the data center allows access to they are consumed by the dominant MIND.