I'm going to show some other important characters who will be in the story and turn into Kamen Riders.
These are some Legend Riders.
Name: Daiki Kaito
Hero Name(s): Kamen Rider Diend.
Other Name(s): Treasure Sniper.
Species: Human.
Home World/Reality: Earth (World of Diend).
Equipment:
NeoDiendriver.
Rider Cards.
K-Touch.
Powers and Abilities:
Dimensional Travel.
Temporal Freezing.
Ridewatch Creation.
Temporal Protection.
Expert Thief
Expert Marksmanship.
Backstory: A phantom thief and treasure hunter from the World of Diend. Daiki knew, and fought both with, and against, Tsukasa Kadoya, the original Kamen Rider Decade. He first meets the Brown siblings in the World of Legend, to test if Nick is good enough to be Tsukasa's successor as Decade. He then gives Nick his old Diendriver, allowing him to summon clones of other Kamen Riders.
Name: Ho-Oh Kaguya Quartz
Hero Name(s): Kamen Rider Legend.
Other Names: The Golden Decade.
Species: Human.
Home World/Reality: Earth (World of Legend).
Equipment:
Legendriver.
Legend Rider Chemy Cards.
Legend Ride Magnum.
Legend Kamen Riser.
Backstory: A resident of the World of Legend who was saved by the original Kamen Rider Decade, Tsukasa Kadoya. Kaguya becomes a golden version of Decade to protect his world from the Hundred. The Brown siblings first meet him when he brings them to his world to test Nick's "Gorgeousness", and see if he is worthy of being the new Decade. He then gives Nick copies of his Rider Cards, allowing Nick to transform into Kamen Riders Legend, and Legendary Legend.
Here are the teammates who travel the Multiverse with the Brown siblings (or as I call them; The "Dimension Riders").
Name: Pyrrha Nikos
Hero Name(s): Kamen Rider Falcion.
Other Names: The Invincible Girl. The Void Swordswoman.
Species: Human.
Home World/Reality: Remnant (Prime Dimension).
Equipment:
Miló (Javelin/Xiphos/Rifle) and Akoúo̱ (Shield) (formerly, destroyed).
Supreme Sword Bladriver.
Unmarked Sword; Nothingness.
Eternal Phoenix Wonder Ride Book.
Power(s):
Aura.
Polarity (she can control metal via magnetism).
Backstory: Originally a celebrity in the parallel world of Remnant for being "untouchable and undefeatable in battle", with her being on a cereal box, she attended Beacon Academy in the kingdom of Vale to become a Huntress and was a member of Team JNPR (Juniper). However, during the Fall of Beacon, Pyrrha was killed by the current Fall Maiden, Cinder Fall, and her body was disintegrated. She later ends up mysteriously revived in Dimension-1218, and joins the Brown Siblings on their adventures through the Multiverse. She also receives the Supreme Sword Bladriver, Unmarked Sword; Nothingness, and Eternal Phoenix Wonder Ride Book from Nick, this is to show that Pyrrha "came back from the dead, like a Phoenix".
Name: Penny Polendina
Hero Name(s): Kamen Rider Machine.
Other Names: P.E.N.N.Y.. The Winter Maiden (formerly).
Species:
Android (formerly).
Human (currently).
Home World/Reality: Remnant (Prime Dimension).
Equipment:
Floating Array (Sword-Guns). (formerly, destroyed)
Machinedriver.
Power(s):
Aura.
Maiden Powers (Elemental Magic)(formerly).
Backstory: Originally created in the kingdom of Atlas in the World of Remnant, as the first Android to have a soul, she was later destroyed before being revived as a Human and became the Winter Maiden. However, during the Fall of Atlas, Penney begged her ally, Jaune Arc, to kill her in order to prevent the Winter Maiden powers from being stolen by Cinder Fall, with the Winter Maiden powers being transferred to Winter Schnee. Penney then mysteriously ends up being revived in Dimension-1218, with her receiving a Machinedriver from Nick, this being meant to remind Penney "who and what she originally was".
Name: Neopolitan
Other Names: Neo. Trivia Vanille (birth name, formerly).
Species: Human.
Home World/Reality: Remnant (Prime Dimension).
Equipment:
Hush.
Power(s):
Aura.
Overactive Imagination (she can create "physical illusions that can be seen by everyone").
Backstory: A mute and heterochronic criminal from the dimension of Remnant who, after the death of her partner and possible lover, Roman Torchwick, during the Fall of Beacon, hunted down Cinder Fall for revenge for Roman's death, but subsequently joined forces with Cinder, shifting her target to Ruby Rose. During the Fall of Atlas, Neo was betrayed by Cinder and ended up in a dimension called the Ever After, where she continued hunting Ruby and her friends, until she was possessed by the Curious Cat. After being freed, Neo lets go of Roman's death and stops hunting Ruby, she also decides to undergo reincarnation in order to find a new purpose for herself and become something new. She later encounters the Brown siblings when they traveled to the Ever After, and joins them in traveling the Multiverse in a quest for redemption. She has not yet received a Driver from Nick, as she doesn't think she has redeemed herself yet to become a Kamen Rider.
Name: Amber.
Hero Name(s): Kamen Rider Mage (Amber).
Other Names: The Fall Maiden (formerly).
Species: Human.
Home World/Reality: Remnant (Prime Dimension).
Equipment:
Wizardriver.
Wizard Rings.
Power(s):
Aura.
Maiden Powers (Elemental Magic)(formerly).
Backstory: The previous Fall Maiden until her Maiden powers were stolen by Cinder Fall, who became the current Fall Maiden, and later killed by her during the Fall of Beacon. Amber ends up revived in Dimension-1218 and received a Wizardriver from Nick, allowing her to use Magic again.
Name: Kamala Khan
Hero Name(s): Ms. Marvel (formerly). Kamen Rider Marvel.
Other Names: Mystic Marvel (codename). KK.
Species:
Human (formerly).
Mutant-Inhuman Hybrid (currently).
Home World/Reality: Earth (Dimension-616).
Equipment: Marvel Driver.
Power(s):
Morphogenetics (Elongation, Size Alteration, Accelerated Healing, Appearance Alteration).
Hard Light Constructs.
Backstory: Born in Dimension-616, the Prime Marvel Dimension, she ends up being killed by the Emissary while disguised as Mary Jane Watson. Her soul is later revived in a new body thanks to The Five. Kamala's original body gets revived with a new soul, and joins Nick and his siblings through the Multiverse, with Nick building Kamala the "Marvel Driver", allowing her to transform into a Kamen Rider version of her old suit.
Name: Himiko Toga
Hero Name(s): Kamen Rider Kiva-la.
Species: Human.
Home World/Reality: Earth (Prime My Hero Academia Dimension).
Equipment:
Kiva-la.
Power(s): Transform (she can transform into a physical lookalike of another individual, as well as copy their voice. She can only transform into people whose blood she had ingested).
Backstory: A member of the League of Villains and that Vanguard Action Squad, and an A-Rank Villain, from the prime My Hero Academia Dimension, she transfers all of her blood into her former enemy, Ochaco Uraraka, saving Ochaco's life at the cost of her own during the Final War. She later gets revived in Dimension-1218 and goes on a quest for redemption through the Multiverse with the Brown siblings as a Kamen Rider.
Name: Zein.
Hero Name(s): Kamen Rider Zein.
Other Names: The Dimensional Savior.
Species: Artificial Intelligence.
Home World/Reality: Earth (Dimension-1218).
Equipment:
Zein Driver.
Zein Cards
Backstory: An artificial intelligence of unknown origins that assessed the "good intentions" of humanity and was suddenly born into the network. By existing on the internet, it had kept the world under surveillance for some time, with even mega corporations like Smart Brain not exempt from it. After it's defeat at the hands of the "Outsider Riders", the Zein Driver ended up in Dimension-1218, with Nick restoring Zein's programing as an ally.