A swirling, turbulent mass of dark energy infests the center of Pop Star. Dark Matter has attempted to keep you out of its home realm, but the power of the Heart Stars has opened up this chaotic zone. The happiness and gratitude contained in the Heart Stars form the Love-Love Stick, a powerful weapon capable of destroying Dark Matter. Your final challenge lay ahead, do not give up for the sake of Pop Star!
Boss: Dark Matter
This battle is fought entirely in the sky, and you can move in any direction you want because of the flight granted by the Love-Love Stick. However, you would definitely want to stay mobile, as Dark Matter's attacks and movement are tricky to dodge. Other than bumping into you, Dark Matter has two attacks. It can either launch the orange orbs around it at you or fire dark bolts of electricity from its eyeball.
The Love-Love Stick is your main form of attack, capable of dealing damage close-range and through heart-shaped projectiles. The safest way to deal with this boss is to keep your distance, as you want to conserve as much health as you can. Therefore, using the Love-Love Stick's projectiles to chip away at Dark Matter would be the wisest tactic. The orange orbs that Dark Matter launches at you aren't too threatening, as you can destroy most of them as they approach you by simply swinging your stick. You can't deflect Dark Matter's lightning bolts though, so be more careful with that attack. Gooey can still be summoned during this battle, and it can actually launch stars at Dark Matter to help you defeat it.
Even if you defeat Dark Matter, your worries are not yet over. An even bigger eyeball appears, presumably the leader of Dark Matter. The being known only as Zero.
Zero's attacks are simple and predictable, but they are difficult to dodge, and any loss of health you've suffered from the preceding fight with Dark Matter will make this battle even more difficult. Zero is much bigger than Dark Matter, so it is easy to hit, but also hard to evade from. It will mostly launch miniature Dark Matter at you, as well as propel high pressured blood at you. The mini Dark Matters can't be destroyed, so you must dodge out of their path. The blood can be destroyed, but only be a melee attack, so it is advisable to steer clear of them as well. Occasionally, it can charge offscreen, becoming smaller as it reappears. It will shoot out tons of blood that fly in unpredictable directions, which can deal increased damage to you. Again, keeping your distance and focusing on dodging Zero's attack is the best strategy to employ here.
Once you deplete Zero's health meter, Zero will detach its red central eye as a desperate attack. The eye can only hurt you by ramming into you, and it has less health than Zero. Continue dodging it and pelt it with projectiles and you will eventually defeat him in a few hits.
Zero's plan for domination has failed, and it violently explodes in a gruesome fountain of blood. The rest of the dark cloud disperses, and colorful rings form around Pop Star. Congratulations, you have completed the main story of Kirby's Dream Land 3! However, there is still one challenge left for you. The minigame Boss Butch is now accessible from the menu screen, featuring boss battles back to back without any extra lives or healing. Only after clearing this mode will you attain 100% on your game file.