The Emperor's Last Stand(Emperor of the Universe‪)‬

The Emperor's Last Stand is the third and final hilarious intergalactic Emperor of the Universe adventure by David Lubar.
Nicholas, Jeef, and Henrietta the gerbil face their most existential crisis yet when the universe is attacked by beings from a parallel universe intent on conquering every other parallel universe. If Nicholas fails in his mission to defend the universe, it’ll mean the end of life itself. …