The Fake Demon Lord

Lapis Lazuli Fardom, the current Demon Lord, is betrayed by her council when they establish a treaty with the Humans behind her back. Having framed many evil deeds against her, both the Humans and Demons set up an ambush to kill Lapis off. Moments before she is killed, a loyal vassal sacrifices her life to tear open a rift in space sending not only Lapis, but also the current Heroes summoned into the rift. When they are finally released, they realize they are suddenly in an entirely new world with races they'd never seen before at war. In this new world, what role will Lapis chose to take up and how will the release of an old Demon Lord into the new world affect the current balance of war?