This page contains Yuudai's relations to other known characters.
- The two didn't interact much at the time of their meeting, but they appear to be on good terms.
- A friend of Yuudai's that piques his interest. Misora also has taken an interest in Yuudai likewise, so the two get along well and offer to help eachother in times of need throughout the ordeal.
- Yuudai's 'owner'. Yuudai was definitely not fond of Hotaru, thanks to her treating him very badly, and was the main source of his death.