Ultra Sword
Ultra Sword (ウルトラソード, Urutorasōdo) is Kirby's Final Smash in Super Smash Bros. 4. Kirby swings out his sword, slashes at an opponent, and, right before it is finished, the Ultra Sword grows even larger, and then Kirby finishes off the opponent, similar to Great Aether in Brawl.
Origin
Ultra Sword is originally from Kirby's Return to Dream Land as a "Super Ability", and Kirby gains this ability once he inhales a Super Blade Knight. This is an upgraded version of the regular Sword ability. When Kirby uses this power, he will wield one of the following: a sword, a meat cleaver, a cutlass, a wooden training sword, Meta Knight's sword, a fan, or a large, blue fish. He will then swing the large sword in an arc that will deal massive damage to enemies who were hit and even destroy terrain. The slice that Kirby performs at the end of his Final Smash where his sword grows is a smaller version of the attack he uses against the final boss.