On the Other Side is a discovery sidequests in Chapter 10, "Rough Waters", in Final Fantasy VII Remake, taking place in the Sewer System. While traversing the sewers, Cloud Strife, Aerith Gainsborough, and Tifa Lockhart find a materia on the other side of the bars.
The materia can be seen from the northwest-most room of six interconnected rooms. To obtain it, the party must head right to the northeast room, south one to the eastern room, then left and down a ladder to a route on the west. Head right (north on the map) to obtain the Warding Materia. This materia is extremely useful for resisting against statuses in the sewers, such as Sleep, if paired with Binding Materia.