Comrade Death/YMMV

Complete Monster: Sarek, Feuerbauch.
High Octane Nightmare Fuel: Sarek's gasses as a whole. His Under World in particular, a chemical lab so frightening that Faux-Hitler is afraid to see where his favorite toys are made. Ultimately, you get to the ending of the story. Sarek and Feuerbauch meet with Dr. Necros, who explains the details of a horrible new gas. "Sarek's Last Word" attacks the nervous system, causing its victims to walk around in circles before dismembering themselves. He goes on to explain that it's effectively perfect and penetrates everything. It's creator bursts into tears as he explains his masterpiece can't be contained and they've all been exposed to it. Immediately after they learn that fact, they realize that Feuerbauch is walking in circles. They spend their final moments in a giddy, half-mad celebration of their impending deaths and begin to drink the Disinegrol. Feuerbauch's final thought is the compulsion to rip off his fingers. The resulting explosion turns a city into a mile-deep pit.
Moral Event Horizon: Sarek is merely an unscrupulous businessman in an immoral industry before refusing to save Janos from wrongful execution. He returns home and tries to convince Cosima to marry him, if not for love then for financial security. After she rejects him, Sarek tells her the truth of Janos' death and fully embraces the concept of "death merchant".