AU Bio: A Swapped Stories AU. In this world, the Bakugan cast still have their Bakugan and the KRs still get their Ziku Drivers. The Bakugan are originally considered just toys, but some real ones can slip right in between toy ones, as was the case with Drago and Dan.

Magnus Black (replaces Geiz)

Magnus realises Dan's potential could possibly turn evil in the future after Nillious warns him, having come from the future, and decides to get rid of Drago as a result. However, Dan manages to find the Bakuball, and rolls him out for the first time in a battle against him. He would come to befriend the other through various situations as they fight against Reed Industries to the point Magnus called him his eternal rival, even if he was still wary of the Genesis Tyrant (Genesis Boukun). During the final battle against Wrath, though, Magnus sacrifices himself for Dan, showing just how much he had come to see him as family, and shows confidence that the other won't go evil. This was proven to be true when Genesis instead chose to release all the power he had, thus undoing the pain he had caused everyone and securing a better future for Vestroia and Earth as he continued to live his life as a normal person in a new timeline where they all live together, even if Gregorius Reed never changed his tune. In this new timeline, Magnus and Dan have a friendship that grows stronger once he fights off Reed once more, deciding on his path as a brawler and nurturing his love for it. Magnus is pretty serious and rarely cracks a smile unless it's around his younger sister Emily, but slowly trusts Dan enough to open up about himself, such as his love for cooking and brawling. 

Dan Kouzo (replaces Sougo and Hiryu)

Happy-go-lucky, upbeat, and also energetic with a touch of arrogance, Dan is always trying his best to make people smile, although his desire to be in the spotlight due to his disorder (histrionic personality disorder) led him to be lonely growing up. In the original timeline, he would eventually become the Genesis Tyrant by harnessing his natural energy to destroy all brawlers and opposition to become unstoppable. However, following Magnus and Emily entering his life, Dan shows a sense of justice and chivalry as he and Drago work together to stop Reed Industries from doing whatever they want with the timeline, meeting different brawlers and learning from them. This leads to Magnus and Emily questioning whether he is genuinely the Genesis Tyrant. However, a quick overview soon shows that Dan's loneliness consumed him when he gained the Genesis power and corrupted him to become the Genesis Tyrant. This truth was found when Magnus and Emily had to go into Dan's memories to find out the truth about his past, also learning Wrath had saved his life in the past and created a conduit within him. Following all of the lessons he had gained, Dan would eventually rewrite the timeline, an idea he got after hearing from Wynton about how the timeline may need to be reset due to how messed up it is. In this new timeline, Dan still gets Drago but lives a good life with Magnus and Emily as his closest friends, leaving his future unclear.

Emily Black (replaces Tsukuyomi)

Gentle but excitable, Emily is Magnus' sister who tries to stop her brother from killing Dan, which confused her because if he's going to become the Tyrant, why is she stopping him? Later on, she realises that it's because she senses the kindness and pain in Dan's heart, allowing her, and eventually Magnus, to guide him through the world of Bakugan brawling. The two would come to accept Dan and eventually consider him a friend, although Emily would gain her own partners shortly before they defeat Reed. In the new timeline, she gets to become partners with them as she steps forward to become herself outside of her brother's shadow. Emily also enjoys spending time with Dan and Magnus despite having struggles with self-esteem.

China Riot (replaces Heure)

She works under Reed despite being 6 years old, still being an impressive Brawler and earning Magnus' respect for her skills. However, she comes off as rude and arrogant, covering up an immense sense of insecurity due to her family ignoring her and having no one to spend time with. This changes when she meets Emily through Reed, and the two end up becoming friends, even if Tripp would cause her death in the original timeline. In the new timeline, Emily and Riot are close and Riot is implied to see her as an older sister; the family she finally got to have which she's really grateful for. 

Colonel Tripp (replaces Ora)

He's selfish, arrogant, and sadistic, willing to hurt anyone to attain his personal goals. However, this thirst for power would backfire in the original timeline, as unlike Riot, no one mourned his death. He becomes a teacher at their school in the new timeline, finally content in his way and no longer selfish, even if he ends up being the comic relief in both the old and new timelines. 

Gregorius Reed (replaces Swartz)

The CEO of Reed Industries and partner to Wrath, Reed's ambitions go beyond just Bakugan collecting and edges onto the complete fusion of Earth and Vestroia. His curiosity would unleash the Geogans and Nanogans, which he harnesses easily to take down the trio. His warped ideals go so far as destroying Dan's childhood by causing the accident that would take his parents' life and then "saving" him by making him a conduit for the power, preparing him as the sacrificial lamb to gain the Genesis power and unaware that Dan would overcome him and kill him before becoming the Genesis Tyrant. Still, he tries to avoid confrontation and instead "cheats" to gain power, such as not showing himself for the first half of the story until after Nillious gained his Nova form, which was when he showed him to try and force Dan to absorb the energy. Sadly for him, his efforts led him to lose, although Dan resetting the timeline still didn't change him for the better. He ends up dying to Magnus unlocking Nillious Nova Maximus, bringing a reign of peace and happy Bakugan brawling. 

Wynton Styles (replaces Sento)

Wynton is excitable yet humble, always chilling out with his friend Lia Venegas and working on figuring out more about Bakugan, which leads him to work with Magnus to figure out the truth behind the distortions in space after helping him and Dan take down the Ventus Maxotaur from Riot. While he is a bit wary about Dan at first, he comes to see the other as a close friend and fellow brawler, even to the point of a rival like Magnus. 

Lia Venegas (replaces Ryuga)

Lia is very upfront, sometimes violent, yet she's always there for her friends, especially Wynton who made her life brighter after she lost her childhood friend Duran Dane to fame. She's also really good with video editing and other creative activities. When she meets Dan, she thinks that he's an okay person until Magnus reveals he's going to become a Tyrant in the future, which sours their opinion of him even if Dan still tries to befriend them. Thankfully, they work close enough that the two begin to see his good points and accept him as him, assisting him in meeting new Brawlers and befriending him as well.

Calloway Storm (replaces Kaito)

He is a phantom thief who is looking for Masato, his former mentee who is observing Dan, hoping to figure out what Dan has that he can steal. A professional who prioritises beauty over everything, he still shows care for Masato, Ajit and Shun, even if he will verbally deny it to the end. While in the end the timeline is reset, Storm helps Magnus fight against Reed when he resurfaces, giving him the means to brawl out Nillious to his ultimate form to take him down. 

Masato Kazami (replaces Tsukasa)

Formerly under Storm's tutelage to learn more about Brawling following his father's death, Masato used to be an arrogant prick who had bitter feelings towards Shun, but following his defeat at his hands, began to see things in a new light, allowing him and Shun to mend their relationship and work together to keep the balance in the world. They are soon joined by Ajit, and Storm comes along once in a while to help them against stronger threats. 

Ajit Storm (replaces Yusuke)

He is taken in by Storm as well, but Storm's ideology ended up clashing with Ajit's, leading him to meet Masato and join his team as they work to keep the timeline safe. He is able to fight on his own and has a sense of justice, but also relies on Pharol when battling other Bakugan. An alternate version of him nearly kills Masato, yet he is eventually revived due to everyone's efforts. 

Shun Kazami (replaces Natsumi) 

Shun is Masato's cousin who he hated due to his lucking out in life despite Shun having his own pressures with being the heir to Kazami Holdings. He is shy but also prepared to fight for his friends if needed with the aid of Hydorous, able to strategise and make the best paths to victory if he has enough time, but bad at improvising on the spot, which is where Ajit fills in the gap through his contextual intelligence. He ends up having to take down Masato when he gives in to the darkness, but Masato returns thanks to their efforts. 

Duran Dane (replaces Kasumi)

He is a vain and selfish actor who was childhood friends with Lia before his rise to fame led him to have a fall-out with her as he abandoned her to work with Everett Ray. However, he ends up losing Nobillious to Everett Ray when he begins working under Viloch, leading to Duran getting his long overdue smackdown from Lia.

Sougo Tokiwa (replaces Dan)

He, Geiz and Tsukuyomi have been friends for a long time, but when the Second Great Collision happened, they were at the epicenter of it, leading them to acquire the Ziku Drivers. In time, they begin fighting against Another Riders that threaten their home, although they do try to protect the general population and help out in suit. Sougo is an upbeat yet somewhat grey-moraled member of the 9-to-5 group as they call themselves; while he will fight for what's right, he's also willing to use any means necessary for that. This puts him at odds with Geiz who believes in fair fights and refuses any other way, but as they grow to become more proficient, they begin adopting the other's beliefs internally; a fact Tsukuyomi finds funny and teases them about often. Sougo is known as Kamen Rider Zi-O, as he named himself cause he found it funny that everything began as they neared the 2020s. 

Geiz Myoukouin (replaces Magnus and Shun)

While a hot head and serious guy, Geiz has a funny side in the form of his shyness and tsundere self, although he always tries his best to do the right thing even if it costs them the battle, much to Sougo's annoyance. He comes to understand the rationale behind Sougo's actions after a loss nearly hurt Tsukuyomi gravely, but still keeps to his usual philosophy if possible. He also takes his responsibility very seriously, especially when the Another Riders begin popping up. He is known as Kamen Rider Geiz, as he didn't feel the need to be too creative with names. 

Tsukuyomi Alpina (replaces Emily and Wynton)

A calm pacifist who snarks, Tsukuyomi is the only girl of the main trio at first before Ora joins them, and she is immensely relieved by this fact due to how exhausting it is to deal with the guys on her own. She is one of the last to gain her Ridewatch despite owning a Ziku Driver, which does not help her self-confidence, but she does still assist with information gathering when the Another Riders show up. Over the course of their fights, she is the moral compass of the two and balances them out, even if she does worry about the consequences of their actions. She ends up becoming Kamen Rider Tsukuyomi, as she feels she doesn't have to be too creative.

Ora (replaces Lightning)

She joins the team shortly before the Second Great Collision, being a slightly unhinged but nonetheless hilarious person to be around. While she struggles with her morality being blacker than most of the team, she slowly comes to embrace it, allowing her to be more grey in that area but also remain friends with the others. She and Sougo get along in that aspect, much to Heure's jealousy. She ends up becoming Kamen Rider Aura, which is similar to her actual name. 

Heure (replaces Lia)

He joined the group before Ora and Hiryuu, and he cares immensely for Sougo, having been protected by him at one point in his life. Because of this, he wants to help him the best he can, but struggles with finding the right balance for it due to his own attachment issues. He ends up working through them as they fight, and Heure is the second last to gain his Rider form before Tsukuyomi. He ends up becoming Kamen Rider Mokai, a mix of Kikai and Moku (wood) due to his robotic and natural elements. 

Hiryu Kakogawa (replaces Ajit)

He is the final member of the group, meeting Sougo when he protected him during the first fight against Swartz. Hiryu is then approached by Swartz's henchmen and warped to his side to combat the 9 to 5 gang, only to eventually understand the truth and switch sides once more. He is detached and snarky, sometimes downright hostile towards others, but in the end, he has a good heart that gets to shine as they work together more, eventually becoming a true friend to them. He ends up becoming Kamen Rider Another due to being Sougo's counterpart in a way.

Swartz (replaces Reed, Tiko, Haavik, Wrath, Storm) (inspired by V)

The main antagonist of their fights and the reason Sougo, Geiz and Tsukuyomi are Kamen Riders, he is Tsukuyomi's brother who abandoned her at a young age following their parents' death. Swartz is egoistical and won't stop until he has all the power in the world, trying multiple times to steal the group's Drivers and failing, of course, to recreate it due to Woz's interferences. He also wiped Tsukuyomi's memories of him so that she would be helpless in the fight against him, but she only recalled him during their first final battle and became a Kamen Rider in the process, defeating him alongside her friends. However, his numerous contingency plans become a nuisance to the group, and even if he's dead his presence is still felt throughout the entire thing. 

Woz (replaces Benton)

He helps the gang from behind the scenes, known only to Sougo at first due to him erasing Geiz and Tsukuyomi's memories to ensure privacy. But soon enough they find out and slowly begin working together, although Swartz did try to get back at Woz for interfering. He is also the one who helps Tsukuyomi recover her memories, and eventually takes up his own Ziku Driver to help the team. While enigmatic and preferring to stay friends with Sougo due to how he had helped Woz in the past by encouraging him, Woz eventually opens up as a sweet tooth and a story loving friend who eventually becomes a writer, chronicling their adventures together.