Dennis serves in the Penguin Empire, a faction of humanoid penguin-like entities from an alternate dimension. As a mecha pilot within their ranks, he engages in combat missions opposing the protagonists. Members of the Empire adopt English names—Dennis included—reflecting their penchant for whimsically adopting linguistic conventions.

During an operation, a scorpion’s venomous strike nearly claimed his life until the Empire’s erratic teleportation technology intervened, warping him to safety. Known for randomly displacing objects or biological traits from organisms—such as shuffling memories, bodily fluids, or articles of clothing—the malfunctioning device underscored its hazardous unpredictability through his survival.