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.
Unlike the other Super abilities, Ultra Sword will randomly change the weapon used when attacking.
The Ultra Sword is the only Super ability that has a revamped song when acquired which is only used in three instances: the Grand Doomer battle, Grand Doomer EX battle and the final stage of Dangerous Dinner.
In the Magolor Soul battle, for one of his moves, he uses two darkened Ultra Swords. In Extra Mode, he uses two darkened Galaxias for the attack, possibly as a reminder that Extra Mode makes enemies stronger.