The Death Metal Voice embodies Retsuko's suppressed rage and emotional turmoil, stemming from workplace mistreatment and personal frustrations. This manifestation occurs solely during her private karaoke sessions, where she channels daily stressors—like sexist superiors, excessive workloads, and social anxiety—into guttural screams. The vocals feature distorted growls and aggressive lyrics, creating a stark contrast with her typically timid demeanor.

Over time, this outlet evolves from a solitary coping mechanism into public performance. By Season 3, Retsuko integrates her death metal vocals with the idol group OTM Girls, transforming private catharsis into artistic expression. This marks a shift from hidden release to public embrace, though the voice remains rooted in emotional regulation. The vocals retain their Japanese delivery in most international dubs, maintaining consistency as Retsuko's raw emotional signature.

The Death Metal Voice directly impacts Retsuko's relationships. A televised outburst accidentally bad-mouthing her boss, Ton, earns her the derogatory nickname "Short-Timer" and jeopardizes her job stability, highlighting the risks when her concealed fury surfaces unexpectedly. Despite later public performances, the vocals primarily symbolize her internal struggles rather than defining her core identity.

No narrative developments alter the voice's fundamental purpose. Even as Retsuko explores marriage, political campaigns, and career changes, the vocals persist as her unchanging outlet for acute stress. Her evolution lies in publicly embracing this aspect, while its function remains tied solely to immediate emotional release, not personal growth or resolution.