The Legend of Avalora the Great Kingdom
This world is called Avalora the Great Kingdom
Avalora comes from Aval (life/root) + Lora (light/lore). The world was literally grown from the Eternal Heart of the World Tree in the center. The two capitals - Sairo in the West and Shirakawa in the East - are the two branches of the same root. The Celestial Gorge bridges are what keep Avalora from splitting in two.
Without the great tree of life, the world will die, this giant tree helps keep the world in balance
Home for humans, demi humans, elves, dwarves and even animals including, mystical creatures and prehistoric animals.
Sekaiju no Kuni means The Land of the World Tree
Their great guardian, the white bird of heavens, Amano Shiratori to protect the tree and the great evil from the ocean, Yamata no Orochi that awaken by the great evil that wish to destroy that balance