Dark Valley, the main area of the Onii Kingdom
|Regions||Meadow over the Bridge|
Thrown Pot Mound
Valley of Memories
The Onii Kingdom is the first kingdom that Corobo explores, ruled by Onii King. It is located in the southeast of The World, and is inhabited by many Onii, most of which leave and join other kingdoms after the Onii King's defeat. Later, wild animals overrun the Dark Valley.
Including Onii Grounds
- 2 Treasures (Toy Staff, Parasol)
- 9 Art pieces
- 3 Wonder Spot locations
- 2 Crashed UFOs
- 1 Flying Machine part
Names in other languages
|French||Vallée de King Démon||King Demon's Valley / Onii King's Valley|
|Spanish||Reino de los demonios||Kingdom of the Demons / Kingdom of the Onii|
- The Onii Kingdom is the kingdom with the most regions, one of only two kingdoms to have different pieces of music between regions (the other being the Tiptoe Kingdom) and the only kingdom to be partially conquered by Corobo before being fully conquered later.
- The shape of the Onii Kingdom on the map after the defeat of the Onii Man heavily resembles the shape of the US state of Georgia.