0² (Zero-Two) is the mastermind and Final Boss behind the events of Kirby 64: The Crystal Shards, fought in the Dark Star. It bears some similarities to Zero from Kirby's Dream Land 3, but it is not known if they are the same character. Collecting all Crystal Shards before the Miracle Matter battle is required to meet 0², or the False Ending is triggered.
0² has a halo, a pair of wings (which are dark red at the tips), and a dark red eye. It also has a cactus-like appendage on its underside, a bandage under its halo, and a spike at the bottom. 0² also releases blood (confirmed to be such by the credits illustration of 0² and the game's ESRB rating in Kirby's Dream Collection Special Edition) when its eye is hit, making 0² and Zero the most maturely depicted bosses in the whole series. Its halo and wings may suggest that 0² is a reincarnation or angelic form of Zero.
0² has only two forms of attack: firing explosive orbs from its eye, and releasing green gas when its underside is out.
Kirby uses Ribbon's Crystal as a weapon during the battle, and Ribbon uses her wings to guide Kirby around. 0² starts off impervious to any attack, and Kirby must stun it by striking its eye 30 times. Then, Kirby and Ribbon can fly to its halo and shoot it 10 times, after which it vanishes and the bandage is struck. 0² also flips over and reveals a long, green, thorn-like tail at the bottom. From there, either the wings or the tail can be hit. Kirby must deal enough damage to the tail before it retracts, repeating the battle cycle.
While 0² is stunned, it is possible for Kirby to destroy its wings by shooting at them, resulting in 0² moving a lot slower. This also leaves 0² more susceptible to damage, and Kirby can strike 0²'s halo without the need to stun 0². After enough damage is done, 0² is defeated, and it explodes with the Dark Star.
If the L or R buttons are pressed during the fight in the Virtual Console versions, the camera will rotate.
- Main article: 0² Battle
- If the player pauses the game in Dark Star, the "Try Again" option (which functions the same as "Quit" in other games) will be replaced by "Tough It Out!" (がんばる, "do your best", in Japanese), which functions the same as selecting the "Continue" button, so the player cannot quit the battle.
- This does not happen in the game's Boss Battles mode, as pausing the game there even when battling 0² will display an "Accept Defeat" option, which lets the player get out of the battle as if Kirby ran out of health.
- Before the fight with 0² begins, the boss briefly shows a strange less-threatening face, with two black dots for eyes and the closed main eye serving as a smiling mouth. Why it briefly looks like this before changing to its look during the fight is unknown, though it may be a feint based on 0²'s "concept art" in the False Ending credits of the game.
- The background for this boss fight is the same as the pool on the ground of The Divine Terminus in Heroes in Another Dimension once three dimensions are cleared and when fighting Morpho Knight in either Guest Star ???? Star Allies Go! (version 3.0.0. only) or Soul Melter of The Ultimate Choice as Adeleine & Ribbon, Dark Meta Knight and Daroach.
Sketch of 0² from the False Ending credits of Kirby 64: The Crystal Shards