Akira Kumon
One of the two protagonists, known as Demon King Commode. His name (九門開 in japanese) translates to “Ninth Gate Open”. The surname Kumon itself, originates from that of a guard who protected the Kyoto Imperial Palace’s ninth gate during the Heian period.
Valaris III
One of the protagonists, also known as the Demon King. Likely inspired by the Dragon Quest IV antagonist Psaro.
Durgolem
A familiar and server of the Demon King.
Yorozuya Shinigami 