Barrier Materia

The Barrier Materia is a Spell Materia. It contains spells that protect Cloud and his allies from physical and magical attacks.

Location
Behind Kakariko Village is the town's graveyard.

Go here anytime between 12:00 midnight and 3:00 a.m. You'll notice that the gate is now a conduit into the Spectral Realm. Pass through it and you'll be faced with a group of enemies, specifically a couple Poes and a few Sluagh. Fight until all of them have been defeated (tip: use the graveyard's wide open space to your advantage).

Once you're done, go over to Dampe the caretaker's house. He'll talk to you about how he was given a charm to "keep away bad spirits," and how its only use is as a paperweight. Dampe gives it to you as a reward for clearing the graveyard of all the spooks. This so-called charm is actually the Barrier Materia.

Spells
The Barrier Materia has four spells, each one more powerful than the last. They must be purchased in sequential order.

Barrier (10 MP); Innate
When cast, this spell protects Cloud or an ally. For a duration of 30 seconds, all damage taken from physical and magical attacks is reduced by 10%.

Barria (25 MP)
This spell is over twice as strong as its predecessor. When cast, it protects Cloud or an ally. For a duration of 60 seconds, all damage taken from physical and magical attacks is reduced by 25%.

Barriaga (50 MP)
The strongest of the three basic Barrier spells. When cast, it protects Cloud or an ally. For a duration of 90 seconds, all damage taken from physical and magical attacks is reduced by 50%.

Reflect (75 MP)
Reflect protects Cloud or an ally as well as harms enemies. For a duration of 120 seconds, half of all physical and magical attacks will rebound, causing the attacker damage. Note that elemental effects that are reflected will likely not hurt their user.