After awakening, the demonic Ogdru Jahad gave birth to the 369 Ogdru Hem. The Ogdru Hem are essentially weaker versions of their parents, but even so they wield unimaginable power. All of the Ogdru Hem were imprisoned by the Watchers, but many are now re-emerging, with the aid of Rasputin and other agents of the Ogdru Jahad.

Many of the Ogdru Hem have no bodies and exist, invisibly, in the air. These evil spirits are used to help raise the Ogdru Hem that have bodies (such as Katha-Hem) out of their earthly prisons