Ultra Sword is an upgraded version of Sword. Unlike other Super Abilities, the Ultra Sword is also used to finish off two bosses - Grand Doomer and Magolor's first phase (as well as their EX versions). It also is used in the penultimate level of the game to defeat every mid-boss (except Super Bonkers), obliterating each in one chop.
Kirby sweeps a sword, cutlass, kendo stick, meat cleaver, Galaxia, bluefin tuna, or a golden paper fan in a wide arc in front of him.
Ultra Sword appear as Kirby's Final Smash in Super Smash Bros. for Nintendo 3DS and Wii U. It replaces Cook, Kirby's Final Smash from Super Smash Bros. Brawl. When used, Kirby will change his appearance to that of the Ultra Sword Super Ability. He will slash at his opponent several times in quick succession as they are unable to move, before performing a finishing blow and sending them flying.
Unlike the other Super Abilities, Ultra Sword will randomly change the weapon used when attacking.
This makes Ultra Sword one of the few abilities to have a multi-form attack; the others being Stone, Archer, and Circus.
Upon using Ultra Sword to defeat Grand Doomer (EX), he always initially uses the cutlass. This is most likely a reference to the fact that it was his default sword before the game officially came out.
The Ultra Sword is the only Super Ability that has a revamped song when acquired which is only used in two instances: the Grand Doomer (EX) battle and the final stage of Dangerous Dinner.
In the final phase of the Magolor battle, for one of his moves, he uses two darkened Ultra Swords. In Extra Mode, Magolor Soul instead uses two darkened Galaxias for the attack, possibly as a reminder that Extra Mode makes enemies stronger.