Daemonites

In their first appearances, they were described as unable to survive long without a host (or just unable to breathe on Earth without a host, depending on which writer you asked). That aspect was quickly retconned/forgotten by later writers.

The Daemonites on Earth were mostly fanatical freedom-fighter/terrorist types who would do anything to defeat the Kherubim. The ones seen on Khera in the later WildC.A.T.S. series were downtrodden third-class citizens (below even the Titanthrops) confined to segregated ghettos and reservations. Their home planet was described as mired in postwar poverty, and kept that way deliberately for thousands of years after the war by the Kherubim victors.