- It is unknown how Tomoe and Akura-ou first met or how they became comrades.
- Akura-ou literally translates to 'Evil King.'
- Akura-ou is sometimes referred to Akura-no-Ou.
- Akura-ou has the same eye color as Tomoe in the manga.
- Akura-ou is taller than Tomoe, in his original form. In human form, he is shorter.
- Akura-ou was shown in the last episode of the first season in his human form.
- He already met Nanami in the past.
- Akura-ou is an Akuma, which in English means "demon."