Walkthrough
The final world in Story Mode, believe it or not, shares the same name as the game itself: Kirby Star Allies. This world is accessed once you have defeated Hyness with Kirby and Friends in Far-Flung Starlight Heroes, directly after Hyness sacrifices himself and the three generals in order to revive the dark god known as Void Termina. This world has zero Levels or Rainbow Puzzle Pieces whatsoever; its sole purpose is for the Final Boss Battle against Void Termina.
The battle against Void Termina will take place in five separate yet distinct stages. Each stage will alternate between Kirby firing at Void Termina using the Star Allies Sparkler and battling inside of Void Termina's own body by foot. Within the first four stages, you will have to deplete Void Termina's Stamina Bar with Kirby. In the final stage of the epic battle, you must engage in a pushing contest with Void Termina, with using the Star Allies Sparkler Finisher to finally defeat the dark god. Defeating Void Termina completes the level, and thus completes the Main Story Mode of Kirby Star Allies. Congratulations!