Akaheru

Red Hell is one of the territories in JAPAN.

Trivia
Red Hell is a reference to the real-world professional baseball team Hiroshima Toyo Carp (広島東洋カープ). The team was nicknamed 赤ヘル the Red Hell during its golden era from the 70's to the late 90's (they wear red uniform).

The location of Red Hell corrpesonds to Hiroshima Prefecture of real-world modern Japan, or the provinces of Aki (安芸国) plus Bingo (備後国) of the warring states Japan.