"Subterranean Wars" was a five-part storyline running through some of the Annuals from Marvel, in 1991.

In Subterranea, the Deviants, under Brutus, begin a war for territory with the other underground empires.  Pushed back, the lesser powers are briefly forced to fight the surface-dwellers, before both teams of The Avengers unite to defeat the Deviants.

ALL five parts are included in this torrent for your downloading/perusing pleasures.

These are not my scans.  All praise and glory to the original scanners, please.