0 (Kirby)

Zero was the main antagonist for a portion of the Kirby series, whose influence continues to affect the series. It was an entity devoid of emotion who tried to seek happiness, then lashed out on Pop Star when it couldn't. It is the creator of Dark Matter.

Backstory
Zero's story is unknown. All that is known is that it is an entity, possibly the God of Misery, who has spent a long time trying to achieve happiness. It eventually gave up, and decided if it couldn't be happy, no one would. It created Dark Matters to go and destroy anything that could get in its way.

Kirby's Dreamland 2
Zero found Pop Star, and commanded one of its Dark Matter to possess the king. This Dark Matter didn't go through, and became Gooey, causing him to be kidnapped several times in a bag. Zero sent another Dark Matter. The Dark Matter possessed King Dedede, and forced him to do terrible things. Kirby defeated Dedede, but the Dark Matter revealed itself and fought Kirby, but was killed.

Kirby's Dreamland 3
Zero was disappointed in its minion's failure, and commanded another Dark Matter to possess Dedede again. Zero then came down to Pop Star and streched multiple limbs of darkness across the planet. Kirby one by one defeated its tentacles, then encountered the Dark Matter. Kirby drove it out of Dedede and into the Hyper Zone where Zero resided. After Kirby and Gooey defeated the Dark Matter using the Love-Love Stick, Zero grew tired of its minions' shortcomings, and revealed itself. Zero at the time seemed to be unaware that love was his weakness, and Kirby defeated Zero. However, in a desperate attempt to kill Kirby, Zero seperated from its body, becoming a small, bloody eyeball. Kirby defeated this, and Zero was killed.

Kirby 64: The Crystal Shards
An unseen force was seen commanding multiple Dark Matter to attack the planet where the Fairies resided, commiting a mass genocide trying to get the Crystal that rested there. Ribbon, a fairy there, ran off with the Crystal, but it was destroyed in the process, scattering all over Pop Star. Kirby helped Ribbon collect the Crystals, and encountered Miracle Matter, which turned out to be Zero trying to copy Kirby. After defeating Miracle Matter, Kirby exposes the Fairy Queen as possessed, and a giant black mass appears in the sky, which Kirby enters. After fighting his way through it, Zero, now in a reincarnated state known as Zero-Two, encountered Kirby. It approached him as a smiling angel at first, but quickly changed into it's demonic form. After a huge battle, Zero was killed for good, wincing in pain as it exploded, seeming to finally have found peace.

Personality
Zero wants to be happy, but for some reason is incapable of feeling emotion. It only seems to feel hatred and misery, wishing for all living creatures to join its suffering.

Trivia

 * Several fans have considered Zero one of the scariest bosses of all time in both of his appearances.
 * Some fans have pitted against Zero against Giygas, as both are known for being incredibly creepy.
 * Zero is similar to Giygas in a few ways:
 * Both are final bosses of their respective games.
 * Both are aliens.
 * Both are uncapable of feeling emotion.
 * Although, it should be noted that Giygas was trained to be unfeeling, as human emotion was deadly to him.
 * Both are known for being extremely disturbing and scary.
 * Both try and become friends with the main character, only to lose their sanity after a brief moment.
 * Oddly enough, a cactus seems to portrude from Zero-Two, which is his weak point.
 * The cactus could possibly symbolize the pain Zero is trying to hold inside of itself, which only hurts it in the long-run.
 * A bandage is also on top of Zero-Two, which some fans have speculated to be where Zero bursted out of it's body.
 * Some fans have speculated that Dark Mind, the main antagonist of Kirby & the Amazing Mirror, is an alternate-dimension version of Zero.