Heibaku

Heibaku [澤吐昆; へいばく] is the world between Kumoshino [the celestial realm] and Tsukarai [the underworld] in the Kiren religion. It can be compared to the realm of Midgard in the Norse mythos, as it represents the plane of the living, nature and ecosystems: Earth. Heibaku was once used as an alternate name for Kanton during the Nittori period, although it often specifically referred to the great plains of the west. 
Literally translated, heibaku means 'place/realm of the flat plains'. It was considered the middle section of the Yōijō, or Universal Tiers, which made up the different planes of existence in the Universe. Traditionally, Kiren belief states that Heibaku lies in the mid-tier, while Tsukarai is located below (literally, an underworld) and Kumoshino is located in the sky or clouds.