Geofront/F Sector

The Geofront F sector is where the group encounters a soul sucking Devil, Scyllamarme, hiding beneath the city of Crossbell.
A series of disappearances of women and girls leads the group there where they find the Devil consuming their souls due to the regrets the girls had in life.
When this sector is visited in Trails of Cold Steel IV it seems to shift into some kind of spiritual or demonic realm that coexists with the real Geofront.