Vallestrella is an enchanted realm filled with sentient magical beings both good and evil. It is the home world to hybridized creatures, most notably the Jaquins, and is ruled by King Verago, Skylar and Nico's father. The entrance resides in a hidden cave that only Jaquins can access.
Humans are not allowed there, because years ago, a human accidentally released Kirin, an evil monster the Jaquins had their biggest battle against, and won, but at a terrible cost. Numerous other dark forces have been imprisoned in Vallestrella as well, such as Marimonda, an evil forest sprite who tried to destroy every city in Avalor centuries ago, but was stopped by the sun birds with ancient magic.