Nikaidou Shou teaches Citizenship at Seitei Gakuen. He measures 179 cm tall, weighs 66 kg, and possesses blood type A. His consistently calm and collected demeanor allows him to handle situations rationally while maintaining composure. Significant interpersonal friction exists with fellow teacher Katsuragi Ginji due to their clashing personalities and approaches. In contrast, he holds the trust of colleague Sanada Masaki and operates under that dynamic. Interactions with student Satorou Goro frequently result in his manipulation by Goro's innocent and carefree nature.