Runic

Runic, also known as Magic Thwart, Attune Blade, and Absorb Magic, identified as Runic Blade in the dialogue of Final Fantasy VI, is a recurring ability in the series. It nullifies most, if not all, magic-based attacks and allows the user to restore MP equal to the MP cost of the spell cast.

Final Fantasy VI
Runic is Celes Chere's ability that allows her to absorb spells with her sword. When she uses Runic, the next spell cast by an ally or an enemy is absorbed by Celes's sword, and she recovers an amount of MP equal to the spell's casting cost. If the spell is of an element Celes is weak to, the MP recovery doubles. If Celes resists that element, the MP recovery is halved. If Celes is immune to that element, she does not recover MP. If she absorbs the element, she loses MP.

Runic does not absorb spells auto-cast from weapons, such as how Ragnarok sometimes casts Flare. If Celes absorbs a party member's spell, the base cost will be absorbed, regardless of whether or not the caster has a Celestriad or Gold Hairpin equipped.

Runic was meant to only be available when a weapon compatible with the ability is equipped, but there is a Swordless Runic bug. Besides the swords, there are other weapons than those Celes can equip that enable Runic: all swords, daggers, spears, katanas, and the Magus Rod. The secret character Gogo may also use the Runic command if equipped with an applicable weapon.

The creation materials state that Runic's power comes from the esper magic channeled through Celes's sword.

This status is not named in-game except as a battle command, this is the status granted by using the Runic command. Celes and Gogo are the only characters who can gain this status.

Once the status is granted, it will absorb the first spell no matter who cast it as long as it is not a spell that ignores Runic. The spell will be absorbed by the user instead of doing what it was supposed to do, and gives the user its MP cost. Runic isn't permanent. Once a spell has been absorbed, the player will have to choose the Runic command again to apply the status. Once the user enters another command, the Runic status is lost. However, a KO'd user will not remove the Runic status. So if the user does Runic, gets KO'd, is then revived, and then a spell is cast they'll still absorb it.

The enemy Bit and the Gold Dragon from the Dragon's Den have a permanent Runic status on them at all time.

Final Fantasy: The 4 Heroes of Light
Spell Fencer's Magic Thwart nullifies enemy spellcasting for four turns.

Bravely Default
The Dark Knight's Absorb Magic starts at the beginning of a turn to nullify damage from magic attacks during that turn, and restores the user's MP by the amount of MP used to attack the user. However, it does not apply to reflected magic damage.

Final Fantasy Dimensions
Attune Blade is a Job Level 8 ability for the Red Mage requiring 220 AP to master. It nullifies all magic spells and restores MP according to the MP cost of absorbed spell.

Final Fantasy Trading Card Game
Celes's card has the Runic ability. For the discard of another Celes card, Runic allows the player to select an opponent's Eidolon and void its effect, then make Celes Active.

Etymology
Руны