Kirby is a major protagonist in Super Smash Bros. Crossover. He is good friends with Yoshi. Kirby had the unfortunate habit of being put in a baby carriage by Sakura. In Season 5, after Naruto, Sonic, and Drago leave the Xavier Institute, Kirby, Ness, and Goku are determined to find them. Eventually, they learned their friends were on Neathia and headed to Bayview to use the portal to Neathia. After arriving, they encounter Cyborg Helios. By working together, and with Naruto, Sonic, and Drago helping out, they manage to defeat Helios for the first time. Kirby, Goku, and Ness decide to stay on Neathia to train with their friends as Naruto, Sonic, and Drago aren't ready to leave yet. They return to Earth in the Season 5 finale and defeat Dark Marth once and for all. In Season 6, Kirby plays a prank on Yoshi by filling his shoes with mud. They are soon distracted when Naruto and Drago are hit by an explosion, courtesy of Bowser, and are blasted to Peach's Castle. Kirby, who was caught in the blast, and Yoshi begin panicking. Yoshi starts saying they have to find them, but is cut off when he spots the Dark Smasher copy of Mario. Yoshi tells to Kirby to go on without him. Kirby refuses as Yoshi has no idea of what the Dark Smashers are capable of, but Yoshi reminds him they can't let Drago fall into enemy hands while Razenoid is still in his body or they'll twist the Chaos Bakugan to their advantage. Kirby then leaves to find Naruto and Drago. Luckily, Kirby arrives just in time to save Naruto and Drago from Bowser and Bowser Jr. before engaging the two in battle. By using teamwork, and thanks to Yoshi's intervention, Kirby, Naruto, and Drago manage to beat Bowser and Bowser Jr. In Season 6, Kirby battles Bowser yet again and despite having a disadvantage at first, Kirby eventually pulls out the win. In Season 7, Kirby battles against Cell in reverse to his battle with Bowser in Season 6, meaning despite having the upper hand at first, Kirby loses the fight and Cell tells him to tell Naruto to come to the Mushroom Kingdom and to bring the Chaos Bakugan or he'll be very dissapointed. In Season 13, Kirby battles against Psycho Kirby following his rebirth, but he is defeated when Dark Pichu and Zombie Spider-Man arrive with Samus, whose enhancement has driven her insane, who quickly proceeds to drain Kirby of his energy before Psycho Kirby blasts Kirby with the same attack that he used on Sonic. Before dying, he tells Sakura, who had arrived with Meta Knight when he sensed Kirby was in trouble, that he actually enjoyed being put in the baby carriage, and he tells Yoshi he'll never forget him. Kirby is revived at the end of Season 13. In Season 20, Kirby moved to Smash City, and later fights against Deidara of the Akatsuki, and learns Madara Uchiha is alive. Kirby later leaves when Piccolo arrives to help, but goes back when he sees smoke billowing from Piccolo's location, and finds that Nagato impaled him. Kirby later witnesses the final battle against Samus Aran. At the end of the second arc, Kirby spots the Millennium Ring and starts to cry, apparently feeling bad for Yami Bakura, only to eat the Millennium Ring. In Season 32, Kirby is conflicted as to whether he should side with Meta Knight or Marth and is later sent to Subspace as a trophy, but is freed by Meta Knight who asks if Kirby knows his parents. It is then revealed that Kirby was an orphan as a child, something that never bothered him until now. Kirby then learns from Meta Knight that Galacta Knight is his father and that Meta Knight is his older brother. Initially shocked, Kirby becomes happy knowing he has a family. However, Kirby's happiness is cut short when Meta Knight and Galacta Knight both die from their wounds since they fought an intense battle. Devastated, Kirby declares war on the species responsible for his family's separation, the Dark Matter. While Kirby is able to get in a few good blows on the Dark Matter, it ultimately flees because it wants to test the trust of the heroes, with Kirby in vengeful pursuit. In Season 34, Kirby learns from Nazo that he was orphaned so he could develop his full potential, and learns that he was created to protect the Heroes of Legend from Ghirahim and the Revolutionaries. After Nazo moves onto the afterlife, Kirby begins to look for Ghirahim in order to end the cycle of hatred. Kirby later locates Ghirahim after Zero betrays the Revolutionaries and opens a portal to Subspace, where Ghirahim is located. Upon meeting Ghirahim, Kirby declares that he will put an end to Ghirahim's rebellion and restore the peace of the Smash World. However, Kirby is unable to defeat Ghirahim since he retreats with Mechtavius Destroyer and his allies. Kirby later helps Meta Knight in his battle against the Heroes of Legend, not wanting his brother to die and leave Seeker, Meta Knight and Zenet's infant daughter, without a father figure. During the battle, Kirby realizes that he and the Heroes of Legend aren't that different, and could've turned out the same. At the end of Season 34, Kirby learns that Nazo is his mother's brother. Filled with grief at Nazo's death, Kirby realizes that he was wrong to try and stop the Heroes of Legend, and joins the Heroes of Legend to continue serving as their protector without inner conflict.
Kirby's appearance is identical to his game appearance. After Meta Knight's Last Stand, Kirby is given Meta Knight's trademark mask as a memento to his deceased friend, and the mask later has a hole made in the mouth area so Kirby can exhale after flying. Prior to the arrival of Dark Matter, Kirby took Meta Knight's armor and cape and has begun to wear it himself. Kirby later reverts to his default appearance after Meta Knight's ressurection.
Kirby is cocky and arrogant and does not like it when he is put in the baby carriage by Sakura (It is revealed though before his death that Kirby truly enjoyed the baby carriage). However, he is still caring. This is shown when he doesn't want Yoshi to fight Dark Mario alone. He is very realistic though, as he knows what will happen with the Chaos Bakugan if Drago is taken while Razenoid is still in him, which convinces him to let Yoshi fight Dark Mario.
In Season 32, Kirby shows a more vunerable side to his personality, as when the heroes become divided on whether to kill the Heroes of Legend or not, Kirby is unable to side with either of them. It is then revealed that Kirby is an orphan, so his inability to choose Marth or Meta Knight's side is because he views all his friends as the family he never knew.
Following Meta Knight and Galacta Knight's deaths, Kirby has a darker view on life. While Kirby still trusts his friends, he no longer boasts his arrogance, is serious all the time, and is focused on the destruction of Dark Matter more than anything else. Kirby later returns to his cheerful personality after Meta Knight and Galacta Knight are revived, but lacks his arrogance.
After learning his role as the protector of the Heroes of Legend, Kirby becomes determined to put an end to the cycle of hatred that has plagued the Smash World for so long. After the Heroes of Legend become interdimensional criminals, Kirby's resolve is only strengthened, as he is aware that he could have become exactly like the Heroes of Legend. However, after learning that Nazo is his mother's brother and Nazo's death, Kirby's resolve is shattered, as he comes to believe that he was wrong to stop the Heroes of Legend, resulting his decision to join the Heroes of Legend.
- Kirby's appearance has been copied by Zenet.
- Kirby is the only character Zenet has disguised herself as that was never an antagonist.
- A running gag is that Kirby is treated like a baby by Sakura. However, due to Sakura's defection, Kirby no longer suffers from this gag.
- In Season 4, due to Sakura not getting freed until the finale, Kirby suffered a different running gag where he was constantly mocked for getting tricked by Luigi to set him free while under the mind control.
- Kirby is ranked #6 on the Smash World Grand Prix rankings.
- Kirby being Meta Knight's younger brother and Galacta Knight's son is exclusive to Super Smash Bros. Crossover.
- Unlike in the Kirby games, Kirby can access his Copy Abilities at will in Super Smash Bros. Crossover, which is likely a reference to Milky Way Wishes from Kirby Super Star and its remake, where Kirby could use any ability he wanted after collecting their Copy Essence Deluxe.
- Kirby is able to summon Helpers through his abilities, but unlike Kirby Super Star or Kirby Super Star Ultra, Kirby can summon multiple Helpers in Super Smash Bros. Crossover, although Kirby exhausts himself quickly if he summons 3 Helpers.