Onii Kingdom
Dark Valley
Dark Valley, the main area of the Onii Kingdom
Ruler Onii King
Princess Princess Apricot
Subjects Onii
Terrain High cliffs
Broken pots
Regions Meadow over the Bridge
Dark Valley
Thrown Pot Mound
Valley of Memories
Onii Grounds
Dark Valley Map Icon

The Onii Kingdom is the first kingdom that Corobo explores, ruled by Onii King. It is a hilly region located in the southeast of The World and is inhabited by many Onii. The kingdom is mostly peaceful until King Corobo invades the northern parts of it, inciting a war. To the southwest is the Sunflower Plains and to the north is Castle Town.


The Onii Kingdom had existed for at least hundreds of years before it was invaded by King Corobo. It had a prevalent population of Onii, and was ruled by the Onii King. The Onii King also had friendly diplomacy with King Duvroc, the ruler of the Kingdom of the Jolly. The Meadow over the Bridge was the most recent region to be claimed by the Onii Kingdom before its fall, but would not remain a part of the kingdom for long.

The northern part of the kingdom was guarded by the Onii Man, a Guardian. However, he was slain by Corobo shortly after the king's rise to power, and the Meadow over the Bridge and Onii Grounds were subsequently annexed by the Kingdom of Alpoko. Corobo was unaware that these areas were part of the Onii Kingdom, prompting the Onii King to demand that either Corobo returned the stolen land or faced him in battle. Corobo marched back into the Onii Kingdom, fought the Onii King at the center of his kingdom and won, forcing the Onii King into exile. Corobo also freed Princess Apricot after one hundred years of capture. Leaderless, the Onii population fled the land and immigrated to other kingdoms and wastelands, with a large group making a new home in the Kingdom of the Jolly, likely due to the ties between the two kingdoms. The land was then transformed into the Dark Valley Natural Preserve, and wild animals such as Rodeo Cows and Black Sheep took over. While later looking for parts for Skinny Ray's Flying Machine, Corobo encountered and fought the mysterious Onii Bride, who was presumably meant to be the queen of the kingdom.


The Onii Kingdom features prevalent iconography specific to the Onii, such as piles of rocks, purple-fire candles, trees with tattered flags waving from them, and strange swirling markings sometimes etched in gold into the sides of cliffs.

Meadow over the Bridge

This area is comprised of many trees, some dead, and a lot of the previously mentioned Onii symbolism. The Skinny Observatory is situated in the middle of the Meadow, and is initially closed due to the Onii activity in the area. Liam seems to have visited the area at some point, as there is a sign written by him warning Corobo to put off visiting the Wavy Rock Forest in the west. In the south is an entrance to the Onii King's arena, although it is blocked off by his throne, which features crude drawings on its back. In the south east is a constructible staircase to the Onii Grounds. It becomes Farmland after joining the Kingdom of Alpoko.

Onii Grounds

This area is a flowery meadow in the middle of a ring of hills, and is where the Onii Man was stationed. It acts as a stronghold to protect the entrance to valley areas in the rest of the kingdom. It becomes known as the Former Onii Grounds after joining the Kingdom of Alpoko. Even after its annexation, a community of Onii live within it.

Dark Valley

The Dark Valley makes up most of of the Onii Kingdom's landmass. It is covered with storm clouds under the rule of the Onii King, hence its name. It splits into three paths at the Thrown Pot Mound near the Valley's entrance: the middle canyon path, the inner clifftop path, and the outer clifftop path. The canyon is the route Corobo takes to fight the Onii King on his first visit to the kingdom. Later, Corobo is able to explore the clifftops, the outermost of which includes the first of two Haunted Zones where ghosts can be spotted on occasion.

Valley of Memories

At the end of the Dark Valley lies the center of the Onii Kingdom, where the Onii King is fought by Corobo. It is encompassed by a ring of mountains, and leads to Farmland in the north and the Sunflower Plains in the west. There are many golden markings on the walls here, and an arrangement of stones in the shape of an Onii on the ground. The area is retroactively renamed the Valley of Memories by Princess Apricot, to commemorate the first place she met Corobo.


Very little is known about Onii culture, other than the Oniis' generally playful attitude. They use many different toys, such as pogo sticks, hula hoops, and toy horses. Additionally, they drop toys and sweets upon defeat. The Onii seem to be the architects behind many of the symbolic rock formations and such seen throughout the Onii Kingdom, and appear to live in Montezuma's Castle-like structures in the sides of cliffs, as they can be seen entering and leaving various adits throughout Dark Valley. Prior to Cow Bones defeat, Onii can be seen on the other side of the river that runs past the Ruined Turnip Field, and if they are spotted they will run away. During Corobo's invasion of the Meadow over the Bridge, several Onii can be seen having a conversation about him. Onii culture can be seen retained in other parts of the World after the fall of the kingdom, such as the Dark Valley-esque area known as Near Bony Tunnel.



Including Onii Grounds


Names in other languages

Name Meaning
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 is 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.
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