The neutral kingdom in Fire Emblem: Fates is Valla. Hidden beneath the Bottomless Canyon between Hoshido and Nohr, Valla is an invisible realm whose existence is concealed by a deadly curse.
Valla is ruled by the dragon Anankos, who secretly manipulates events and fuels the conflict between the two surface kingdoms. Its hidden location and mysterious history become central to the Revelation route, in which Corrin refuses to side exclusively with Hoshido or Nohr and instead works to unite them against the threat from Valla.
Hoshido and Nohr are the two kingdoms presented openly at the start of Fates, while Valla is introduced as a third power behind the war. Cheve is a Nohrian territory, not a separate kingdom. The route associated with Valla is Revelation, although the kingdom also appears in parts of the other campaigns and downloadable story content.