Knuckles the Echidna is one of Sonic the Hedgehog's closest friends as well as his secondary rival (with Shadow the Hedgehog being Sonic's main rival). In Super Smash Bros. Crossover, Knuckles is one of the main characters of the series from Season 23 onward. In Season 22, Knuckles is killed by Meta Knight during the psychopath's massacre, but is revived during Samus Aran's siege. In Season 23, Knuckles is patrolling Angel Island when he enters a temple and goes through a room with a glass wall, and sees his younger self (though neither Modern Knuckles or Classic Knuckles are aware of it at first, thinking they are seeing their reflections). However, they are interrupted by the sound of Mechtavius Destroyer's voice, which startles Knuckles and causes Classic Knuckles to go after it. This causes Knuckles to realize he isn't looking at his reflection and he tries to catch up to his younger self. The two Knuckles then wind up running into Mechtavius Destroyer, and are forced into battle with the psychopath. Later, Knuckles is killed by Mechtavius Destroyer after he survives the Spirit Bomb, but is revived after he becomes complete. Knuckles has a much larger role in Season 32, where he leaves the heroes after the defeat of Mechtavius Destroyer after having a falling out with the Heroes of Legend for erasing Tikal's memories, and is shown to be taking care of the amnesiac Tikal and her children with his classic self with the hope of Tikal regaining her lost memories so that Knuckles can learn more about his own past.
Classic KnucklesEditClassic Knuckles is Knuckles' younger self who makes his debut in Season 23 of Super Smash Bros. Crossover. Classic Knuckles is seen relaxing and minding his own business when he sees a silver woman in the sky (Dark Wasp without her human disguise). Classic Knuckles is then hit by a bomb and sees an EggRobo after the smoke clears. Unaware that this is Metal Sonic's doing, Classic Knuckles believes Dr. Robotnik (the Classic Dr. Eggman) is responsible and chases after him. Classic Knuckles then boards one of Metal Sonic's flagships and sees Classic Metal Sonic, Modern Metal Sonic, and Wiseman discussing the current situation. Before he can escape, Classic Knuckles is transported in front of the trio by Wiseman, who tricks Classic Knuckles by telling him that "Sonic and his friends are trying to stop the silver woman from absorbing her "fragments" and becoming complete, which will result in her death". Classic Knuckles is then transported back to Angel Island where he whacks Classic Tails, due to Wiseman's lies. Classic Knuckles is then told by Classic Tails that he is being tricked, but Classic Knuckles is unsure and sends Classic Tails into the Hydrocity Zone so he can think. Later, Classic Knuckles somehow manages to wind up on Earth-616 and goes through the same temple his future self is going through, and thinks he is seeing his reflection. However, they hear Mechtavius Destroyer's voice, which startles Modern Knuckles, causing Classic Knuckles to realize that his "reflection" isn't really him. Despite his surprise, Classic Knuckles chases after Mechtavius Destroyer, with Modern Knuckles following him. Classic Knuckles is more reclusive than his older self, as he is not seen during Mechtavius Destroyer's rampage. Classic Knuckles reappears after a long absence in Season 32, where he is helping his future self take care of an amnesiac Tikal and her children.
- Knuckles was the last member of Team Sonic to become a main character.
- Knuckles' first encounter with his younger self is a reference to how Sonic first saw his younger self in Sonic Generations.