The Sea of Souls is a safe repository for souls in the Underworld. The living sea swirls with the spirits of those who once walked the mortal realm.
The spirits of the newly dead end there journey at Hall of the Lord of the Dead, where they have audience with Samhain and are then immersed in the Sea of Souls, where souls are greeted by ultimate knowledge and are prepared for the next stage of the afterlife. The exact purpose of the souls audience with Samhain is unclear but has something to do with the judgement of the souls.
Those souls who have died at peace with their lives are allowed to enter the Underworld and are placed in the Sea of Souls. In that safe repository, they are greeted by ultimate knowledge and are prepared for the next stage.
Once in the Sea the Souls, the souls are in a trance-like state in their purpose and are uninterested in anything going on around them.
It is unclear where they go after leaving the Sea of Souls for the next stage of the afterlife, but its possible depending on how they are judged by may end up in some hellish realm such as Hell, Hades, or the Abyss, or some heavenly realm.
Behind the scenesEdit
Both the Realm of the Dead and Sea of Souls act in the same role as Limbo, in that souls are held there until they can move onto their next stage of the afterlife.
Only the peaceful dead can be placed in the Sea of Souls, those with unfinished business in the world, and evil souls are prevented from moving on, and forced to stay on the Surface Region, until either peace is brought to them or they become the restless dead that walk the surface.