|Primary caster||Fate Testarossa|
|Japanese name||サンダーブレイド |
|First app.||A's (ep.7)|
Thunder Blade (サンダーブレイド Sandā Bureido) is a "power-up version" of Fate Testarossa's Thunder Rage spell, wherein she focuses each attack into individual swords that can detonate on the command "Break!" Chrono Harlaown has a attack with similar visual effect called Stinger Blade Execution Shift.
Erio Mondial uses a spell also named Thunder Blade in Sound Stage X (disc 2) to fight Mariage. It is cast with Strada in Form Drei (Unwetterform). It is not known if his spell is same as or similar to Fate's.