Manjiro Sano/Synopsis

History
Ever since he was a child, Mikey was under the care and guidance of his martial arts master grandfather. As a result, he underwent rigorous martial arts training and was recognized as a genius. He lived with his grandfather and brother together in the former's dojo.

Sometime around elementary school, Emma Sano came to live with the Sano family. That is when he got the nickname 'Mikey' so his sister did not feel left out with a foreign name. The two eventually formed inseparable sibling bond. That to people who do not know, they appear as close as couples.

In fifth grade, Mikey met Draken when the latter was instructed by older children to bring him to them so he could get beaten up. Mikey takes an interest in Draken and agrees to go meet the older kids. Upon meeting them, Mikey immediately executes a flying kick to the leader's face and breaks several of his teeth. Mikey then nonchalantly invites Draken to hang out with him instead, to which the latter happily agrees to.

In Mikey's first year of middle school, he and some friends decide to form a gang, naming it Tokyo Manji Gang.

Toman Arc
Mikey and Draken visit the fights organized by Masataka Kiyomizu. Mikey is initially shown to be quite carefree and informal, but upon his reception by the audience, becomes more aloof. Despite reactions from the crowd, Mikey does not acknowledge any of them, instead approaching Takemichi Hanagaki. After being introduced, Mikey gives him the nickname of Takemitchy, and decides that from that point onward the two will be friends. Draken and Mikey then break up the fighting ring, declaring that underground fights are not permitted in Toman.

The following day, Mikey and Draken come to Takemichi's classroom. Hearing that Takemichi was being kidnapped, Hinata Tachibana runs after them. Upon meeting Mikey, she slaps him in the face and attempts to leave with Takemichi, but is stopped by Draken. Mikey says he is going to kill the two, but Takemichi protests, and asks him to forgive Hinata. Mikey prepares a punch, but then laughs and says that he was only joking, and that he would never hurt a girl.

Takemichi, Mikey, and Draken then leave peacefully, and Hinata apologizes, saying she misunderstood the situation. Mikey accepts, but reprimands her, saying that her actions could've been bad if he was a dangerous person and calls her a nice girl, telling Takemichi to take care of her. The group bikes to a river and Mikey mentions that he likes Takemichi, because he reminds him of his older brother of 10 years, who had died. He states that he wishes to create an era of delinquents like the one his brother was a part of, and asks Takemichi to assist him.

The following after that, Mikey was seen gathering everyone at the meeting. He announces at the meeting, standing up, stating that they gathered to discuss upon Pah-chin's problem: one of Pah's friends, got caught up in a fight with Osanai, which led to members of Moebius raping his girlfriend, killing his parents and siblings, and taking his money. Mikey asks Pah whether or not he wants to fight Moebius over it, and when Pah agrees, Mikey rallies the rest of Toman to the cause, stating that they’ll have a battle with Moebius on August 3rd at the Musashi Festival.

Deciding to become Draken's "bodyguard", Takemichi decides to follow Draken around to keep an eye on him without permission. He notices Draken going into a restaurant where he thinks he may be fighting with Mikey, but it turns out to be a series of misunderstandings over Mikey not getting a flag in his kid’s meal rice and then falling asleep after eating, resulting in needing to be carried out of the restaurant by Draken. At the hospital, Mikey was seen along with Draken, going to visit Pah's friend's girlfriend. The girl's father appears, yelling at both of them for being there. At first, Mikey was reluctant to bow and show he’s apologetic because he doesn't believe they had anything to do with it, but Draken pushes him into a bow anyway. After the girl’s parents leave, Draken tells Mikey that it is their responsibility to not let outsiders get harmed due to what happens in their world, and that he doesn’t have to bow but he needs to care about others and have a heart. Mikey apologizes and tells Draken he’s glad he’s here with him.

Moebius Arc
Mikey was next seen in an abandoned warehouse, having a meeting along with Draken, Pah-chin and Peh-yan. Takemichi goes towards them, attempting to call off Toman's fight with Moebius, stating that someone is plotting the fight, however, Takemichi can't tell how he knows. Takemichi keeps insisting it's a trap, eventually annoys Pah-chin, threatning Takemichi that he will kill him if he says anything else. Mikey then states Toman will be going to fight Moebius since he made up his mind. As Takemichi states he won't back down, Ken stops Pah-chin, stating that maybe they need to look more into Moebius. Manjiro then wonders if Ken is against Toman. Eventually, Osanai then shows up, ambushing them with a few Moebius members. Osanai then hits Takemichi before being interfered by Pah-chin, who wishes to fight Osanai. Mikey was seen ordering the rest to watch.

However, with Osanai easily beating up Pah, Pah was seen apologizing to Mikey for being worthless, Manjiro states he didn't lose. While Moebius members mock Manjiro and the rest, Manjiro approaches Osanai and knocks him out with a single kick. Manjiro then states that whoever thought that Pah-chin lost to get out of there or he will kill them and as long as he is with Toman, they will never lose to anyone. As Mikey and the rest heard the police sirens outside, everyone attempted to run away. In that moment, Pah stabs Osanai in the back, which shocks everyone. Pah then apologizes to Mikey and tells them to run as he intends to turn himself in.

Following of Pah deciding to turn himself in to the police, Mikey and Draken argued and ended up fighting. Despite of this, Toman then becomes divided into two factions: the Manjiro faction and the Draken faction.

Mikey was then next seen in front of Takemichi's house as soon as Draken leaves. Both of them wonder what the other one is doing there, also stating they are there to see Takemichi, who is their friend. Both Draken and Mikey continiously argued against each other, throwing Takemichi's things against each other. The argument between Mikey and Draken was then stopped by Takemichi, unaware that he has shit on his head. Both Mikey and Draken laughed and run away. They then made up and apologize for their behaviour.

On August 3rd, at the Fire Festival, with Draken being ambushed by Moebius, Mikey was seen arriving on the scene, getting of his bike, realizing he was called somewhere else so that Peyan can be with Ken and break Toman, but wonders who tricked him into doing that. Mikey was then seen fighting against Shuji Hanma, who introduces himself as the temporary leader of Moebius. Mikey attempts to kick him in the head, but Hanma manages to block it. Hanma, with 100 Moebius members, warns Mikey, Mitsuya, Takemichi and Draken not to run, only to realise the rest of Toman gathered, arriving on bikes, ready to fight.

As the fight starts, Manjiro approaches Peh-yan and asks him why he attacked Ken, even thought they have settled things down. Peh-yan doesn't accept that Toman gave up on Pah-chin and starts punching Manjiro. He states that Pah-chin was everything for him and if Toman abandoned him, its natural that he becomes their enemy. Peh-yan knows that Manjiro can beat him in a single hit, but wonders why he isn't fighting. Manjiro pulls Peh-yan's head towards his and tells him to look at him and if he ever smiled about Pah-chin getting caught. Manjiro then asks Peyan to keep hitting him until he is satisfied, but he doesn't want to fight with his own family and wishes Peh-yan to return to them.

Noticing that Draken gets stabbed, Mikey orders Takemichi to take care of Draken whilst he was busy in a fight with Hanma. He was then seen still fighting against Hanma, with the end result of Toman defeating Moebius. Impressed by Mikey's stamina, Hanma tells Mikey that he is about to witness the creation of the most sinister biker gang alliance in Kanto, Valhalla, and re-introduces himself as the first vice commander of Valhalla.

With Draken being sent to the hospital, undergoing surgery straightaway, Mikey then rushes towards the hospital with his bike. He then reassures the people there that Draken is a man of word and he promised him that they will rule the world together, thus he won't die and they need to believe in him. As the operation ends, the doctors come out and inform the group that the operation was success and Ken is alive. The group is happy and celebrates while Mikey is seen alone in a corner crying out of relief.

Black Dragon Arc
In year 2018 in a new alternate timeline, Takemichi fled to Manila, Philippines, to escape the authorities. Remembering something Mikey had told him in the past about his brother visiting Manila, Takamichi finds him there alone in an abandoned building.