Flare Blade

Roy's fully charged flare blade being unleashed upon Donkey Kong and Bowser

Flare Blade is Roy's neutral B move. Marth has a similar move called Shield Breaker. Flare Blade can be charged for up to five seconds by holding the B button, and when fully charged, it does 50% damage and delivers a one-hit KO (except on larger stages, like The Temple). Roy takes 10% damage from the explosion of the fully charged attack. Flare Blade has the potential to break shields when it is charged up to a point.

Origin

This move is based on Roy's Melee critical hit in Fire Emblem: Fūin no Tsurugi, when he has the Sword of the Seals.