Manawall is a magic spell in Final Fantasy VII Rebirth. It is the third spell granted by the 
Barrier Materia. It grants both the 
Barrier, 
Manaward effect, which halve physical and magic damage taken respective.
Manawall covers the 
Barrier and Manawall spells in one spell. Though Protect and Shell also exist, they have slightly different functions, wherein Protect and Shell simply improves the user's 
Magic Defense while barrier and manaward halve the incoming damage.
Use[]
Manawall costs 20 MP to cast. It grants two protective statuses that halve physical and magic damage for their duration. The spell can be combined with other means of resisting incoming damage taken. It is an expensive spell to cast, but can be very helpful in a number of battles.
Manawall outclasses Barrier and Manaward spells and is more ATB-efficient. However, it is even more expensive to cast in terms of MP, meaning players should only cast one or the other against particular attacks or against enemies that rely more of one type of damage.
Manawall can be used effectively when barrier materia is paired with 
Magnify Materia. This allows the user to apply these effects to all party members at once, and is an ideal use case for magnify materia.
Manawall can be helpful with parties including Barret, due to his Lifesaver ability. Because Manawall diverts damage intended for other party members onto himself, reducing damage they receive also reduces damage then diverted to Barret.