Kidou Kaimaru serves as an assistant professor of psychology at Genjōsai University, wielding expertise in psychological studies and computer technology. He recurs as a supporting character throughout the Dream Hunter Rem media, where his academic background intersects with supernatural investigations. Kidou harbors strong romantic feelings for protagonist Rem Ayanokōji, fueling a persistent rivalry with the ascetic monk Enkō due to their shared affections. This dynamic unfolds across multiple installments, including the OVAs Dream Hunter Rem II: Seibishinjo Gakuen no Yōmu, Dream Hunter Rem III: Yumegakushi, Kubinashi Musha Densetsu, New Dream Hunter Rem: Yume no Kishi-tachi, and New Dream Hunter Rem: Massacre in the Phantasmic Labyrinth. His role extends to anthology comics like Party of Rem and Fiesta of Rem, maintaining consistency as an academic admirer without significant evolution or expanded backstory.