Akaio Hishiro was a Ghoul Bishokuya, geneticist, and one of the First Men and founders of Hades. He died more than a century ago during the era of the War of the First. He was the father of Akajimaru, the so-called "Red King". He was responsible for the creation of the Ghoul Territory of Aima: which he named after his deceased wife.
- Akaio Hishiro's first name means "Red Man" and his surname means "Scarlet Castle".