Robert Downey Jr.'s return to the Marvel Cinematic Universe as the villainous Doctor Doom has introduced a character voice with a pronounced Latverian accent that has sparked polarized reactions among fans, with some likening it to conventional supervillain portrayals. The actor's vocal choice was unveiled in a recent trailer and generated considerable discussion within the fanbase about its effectiveness.

Directors Joe and Anthony Russo revealed that the voice interpretation emerged naturally when Downey Jr. improvised the performance during conversations about character details. Joe Russo stated that hearing the voice produced an intense emotional response he compared to the actor's memorable moments in previous MCU projects, suggesting the filmmakers viewed the choice as a defining element of the character.