Mr. Norris’s voice
William’s first impression of Arthur Norris is that of a comedic figure, with a nervous gait and rapidly blinking eyes. William notices that even his voice matches with his appearance, high-pitched resembling a character in a pre-war drawing room comedy.
The enemy fortress
Arthur gets an invitation to go to the police for interrogation. Given his shady conducts and connections Arthur is naturally nervous. He feels as if he has to go into the enemy fortress, which reveals that Arthur has much more to hide than what William assumes.
William the spinster and Arthur the cat
Sudden disappearance of Arthur from Berlin takes a devastating toll on William. He can’t help but feel possessive of the eccentric man, like a spinster who was abandoned by her cat. Comedic as it is, this comparison perfectly describes their relationship, where William is a passive individual who needs the exciting presence of Arthur, and Arthur, despite giving the impression of closeness, isn't afraid to disappear suddenly.
Like creatures demonically possessed
During his time at the Nowaks, Christopher gets more acquainted with the family of his friend Otto than he desired. Tge relationship between Otto and his mother is a complicated and manipulative one. Otto isn’t unkind to his mother but doesn’t see it necessary to help her in any aspect of the household, while the mother prefers her other son to Otto, calling Otto a lazy failure. Nevertheless, the resemblance between them is striking and on one of their violent arguments the narrator notices that their enraged faces look like creatures demonically possessed.