The Keys of Smash Arc is a story arc in Super Smash Bros. Crossover. It is the successor of the Time Eater Arc. This arc is succeeded by Fight to the Finish.
The arc focuses around special keys with an unknown purpose, one of which were acquired by the Heroes of Legend after they defeated Time Eater. It is later revealed they unlock LV 3 of the Smash Core. At the end of the arc, Samus absorbs the negative energy of the Smash Keys and prepares for the final confrontation with the Heroes of Legend.
- Naruto Uzumaki
- Sakura Haruno
- Sonic the Hedgehog
- Zombie Spider-Man
- Ren Krawler
- Fabia Sheen
- Psycho Kirby
- Zombie Wasp
- Sasuke Uchiha
Boo Rock (Deceased)
Professor E. Gadd
Ishizu Ishtar (Yu-Gi-Oh Abridged)
Morton Koopa Jr.
Wendy O. Koopa
Ludwig von Koopa
Yami Bakura (Main Antagonist, 1st half)
Samus Aran (Main Antagonist, 2nd half)
Zombie Reed (Deceased)
- Mechtogan : Coredegon
- Mechtogan : Slycerak
- Mechtogan : Exostriker
- Mechtogan : Mandibor
- Frieza and Orochimaru return in this arc despite their deaths in the Time Eater Arc, meaning they were revived after the timeline damage was repaired.
- Madara Uchiha, Noah Kaiba, and Mutant Elfin managed to avoid getting returned to the afterlife.
- The Pecking Order have finally become a major threat, as they serve as major antagonists in this arc.
- This arc has the largest cast to date.
- Morrigan Aensland, Cloud Strife, and Sora finally play a major role in the series.
- The main cast of the Time Eater Arc play a major role in this arc as well, though Ganondorf doesn't return.
- The Porygon Family were originally alligned with the heroes, but switched sides due to Marik's lack of respect for them.
- Bowser, Samus, and Zombie Reed learn they are the reincarnations of Gigadark Bowser, who is a part of Zorc, and become antagonists again.