With great power comes... the desire for even greater power. Or at least, that's generally the case for demons. They're not necessarily known for their restraint. With the Rage of Demons adventures going, Gale Force Nine is bringing another couple Demon Lords to your tabletop as part of the Collector's Series of minis.
Zubbtmoy is only interested in infecting and controlling others who will then help her spread her influential spores across the entire world. Basically, this is one mushroom pizza you should probably pass on.
Meanwhile, Graz'zt is all about debauchery and desire. Always looking for the next score, he'll happily build up everything around faithful followers... and then watch it all come crashing down. Sort of like the joy of knocking over a house of cards.