Based on the theme of “武藤遊戯 vs 真崎杏子” from “悪魔のリドル,” I will create a color palette that reflects the duel’s intensity, character contrasts, and the overall atmosphere of the series.

 <Duel of Shadows>
1. Shadow Black - 
                            
                            #1A1A1A
                         - A deep, dark black representing the intense rivalry and the shadows of the duel.
2. Mystic Purple - 
                            
                            #6A1B9A
                         - A rich purple symbolizing the mystical elements and the supernatural aspects of the characters.
3. Blood Red - 
                            
                            #C62828
                         - A vibrant red that conveys the intensity and passion of the confrontation.
4. Ethereal White - 
                            
                            #FFFFFF
                         - A pure white that highlights innocence and contrasts against the darker colors, representing the complexity of the characters’ morals.
5. Neon Green - 
                            
                            #00E676
                         - A striking green that signifies the energy and determination of the characters in their battle.

This color palette encapsulates the dark and mysterious themes of the duel, while also highlighting the contrasting elements of the characters involved.

Would you like to explore specific applications of this palette, such as for character designs, posters, or UI elements?