Valhalla is an unseen world mentioned in God of War (2018).
Description
Valhalla is the home of fallen warriors who have been gathered by the Valkyries. These warriors will fight and feast until the day of Ragnarök.
When Odin cursed the Valkyries, they became unable to fulfill their task of gathering warriors who had died in battle. This led to an increase of the dead in Helheim to the point where it was overflowing and the dead were walking around in the mortal realm.
Kratos and Atreus have the option of freeing the Valkyries, allowing them to return to their task and restore balance to the world.