Hive Realms are the result of the Avatar Storm. The Storm ripped some Realms along the membrane with it and fused them to new, disturbing Realms that dot the Umbra. Every mage who tries to access a Realm has good chances of contacting a Hive Realm instead. Most are comprised of blood-red, crumbling stone and have a very thin atmosphere that makes breathing hard. Hive Realms are usually inhabited by Nephandi and alien creatures known as Builders, who serve vile creatures and erect monuments and temple in their honor.