Black Sea (黒海, Kokkai) is located north of the Yellow Sea and borders the three kingdoms of Ryuu, Kyou, and En.
- En - The Kingdom of En is a flourishing kingdom of the Twelve Kingdoms that is between Kei and Ryuu and is one of the four "middle" kingdoms. It is ruled by Shoryu who has reigned for 500 years.
- Kyou - The Kingdom of Kyou is one of the four "middle" kingdoms of the Twelve Kingdoms. It is ruled by Shushou.
- Ryuu - The Kingdom of Ryuu is the northernmost kingdom of the Twelve Kingdoms. It is currently ruled by Rohou.