I couldn't miss the chance to practice my drawing!
Thundaga Blade (サンダガ剣, Sandaga Ken?), also known as Thundaga Sword or simply Thundaga or Bolt3, is a recurring ability in the series. It is oftentimes part of the Spellblade skillset, and is the highest Lightning-elemental Spellblade available, depending on the game. It generally requires the Thundaga spell in order to use it.
Thundaga is a level 5 Spellblade ability that costs 15 MP to cast. When used against an enemy that is weak to Lightning-elemental attacks, the power of the user's attack is quadrupled and pierces the target's defenses.
Thundaga Blade is a rank 5 Command Materia that costs 32 MP to use. It can be obtained as a reward for completing Mission 9-1-2, stolen from Crescent Unit Ventus, found during Mission 2-5-5, and bought from the Wutai Secret Shop for 10,000 gil.
Thundaga is a level 5 Sword Magic spell. It imbues a weapon with a high-power lightning effect for ten turns. This will raise attack power by the amount of the magic effect. It costs 45 MP to use. It can be bought in Eternia for 3200 pg.