Secret Arts, Dance of the Guardian Swords

<Katana World> Play this with [COST][pay four gauges] if your vanguard is armed with a <Weapon>! Retire all of your opponent's front row rear-guards. [CONT]:During your opponent's turn's guard step, this card can be called to (GC) as a trigger unit, and it becomes a Grade 0/[Shield]15000 guardian.