Warlock's Secret Technique
暗黒魔道士の秘技 [ankoku madoushi no higi] or 'secret technique of the dark mage' in Japanese. 暗黒魔道士 has also been translated as 'warlock' in some cases.
Record Keeper

Type: Record Materia, Record Materia Level: 2, Rarity: -
Obtain: drops with a set percentage chance in battle with a Limit Broken Exdeath in the party
Effect: Activates a Darkness ability a second time with a set percentage
Category: Ability