Manjoume Jun has two older brothers.  His oldest brother, Chousaku, is highly influential in the world of politics, while the other, Shouji, is just as influential in the world of finances and economics.  Therefore, Manjoume has always had a lot of pressure on him from the rest of his family to succeed as well, in his area of expertise: the card game Duel Monsters.

As such, he attended the finest dueling preparatory school that money and his talent could obtain admission to, and then when he was fifteen, he began attending Duel Academy.  His talent, as well as his fine grades at the affiliated school, allowed him to start in the Obelisk Blue dormitory, reserved for the top students.

But there was one person who suddenly became a huge rival for him – Yuuki Judai, a new student in the Osiris Red dormitory, reserved for the students least likely to succeed.  Somehow, this kid had managed to defeat Chronos de Medichi, one of the top teachers in the school and head of the Obelisk dormitory.  And even with his significantly more powerful cards, not even Manjoume could stand up to him in an early test duel.  (Or in the practice duel that they attempted to have earlier, but couldn't finish because it was against the rules to be up that late at night.)

His frustration at having lost, and then losing again to Misawa Daichi, a first year in the middle-ranked Ra Yellow dormitory, caused Manjoume to decide to leave Duel Academy.  Unfortunately, his boat capsized in the middle of the ocean, and he wound up accidentally falling off into the water; however, he was saved by a submarine that happened to be driving past.  This is how he met Ojama Yellow – the yellow spirit managed to wake him up (because unlike most other people, he could see it), and a mysterious man on the submarine gave him the Ojama's card after dunking the rest of Manjoume's deck in a puddle.  Yellow decided to accompany Manjoume, much to the boy's chagrin, in the hope that by doing so he could be reunited with his missing brothers.

Manjoume then found himself on the iceberg that was home to North Academy, another dueling school and Duel Academy's greatest rival.  In order to enter the school, one had to have a full deck of forty cards… and Manjoume only had one.  Not that they were impossible to come by – it was set up that there were cards scattered around the island in various locations, the rarer and more powerful ones being the ones that were the hardest or most dangerous to obtain.

Eventually, Manjoume managed to obtain a deck of forty cards, gained entry into North Academy, and defeated fifty students there, along with the current King.  Because of this, he was named the new King of North Academy (also earning the title of Manjoume Thunder) and given the opportunity to represent that school in the upcoming School Duel with Duel Academy… the representative of which would be Judai.

Of course, his brothers televised the duel… and Manjoume lost.  His brothers told him off for being a failure, but Judai and Chronos stood up for him.  After that, Manjoume decided to return to Duel Academy, though he would be demoted to Osiris Red for having missed so much of the year.

It was only a short time before Principal Samejima called Manjoume, as well as four other students and two teachers, to his office to request their help.  Duel Academy had been built atop the place where the three Phantom Demons – cards endowed with such great power that could be used in the wrong hands to completely destroy the world – had been sealed.  This seal could only be opened using seven keys, which could each only be claimed by winning a duel with them as the ante.

Samejima had recently received information that seven duelists would be coming to Duel Academy.  Known as the Seven Stars, they were an organization intending to obtain all seven of these keys and use them to obtain the demons' power for themselves.  In order to protect the keys from them, therefore, Samejima wished to entrust them to the seven best duelists on the island.  Manjoume was among them.

The first Star to appear was a masked man who went by the name of Darkness.  He challenged Judai to a battle atop a volcano, the stakes being that the victor won the key, and the loser would have their soul sealed inside of a blank card.  Judai won, of course, and Darkness was sealed… but his was not the original soul in the body.  As it would turn out, Darkness had merely been controlling a young man: Tenjoin Fubuki, Asuka's older brother who had vanished years before.

The second Star was a vampire named Camulla who sealed the souls of her victims inside of dolls.  She faced Chronos first and won, taking his key and turning him into a doll.  However, she didn't like how the doll turned out, so she discarded it, and Manjoume wound up taking care of it.  Camulla then went on to defeat Marufuji Ryou in a duel (but only because she had taken the soul of his brother, Sho, as a hostage), but she lost when she faced Judai, who had been given the half of an amulet that Fubuki had been carrying and was therefore able to cancel her ability to hold others' souls hostage – as soon as Camulla was defeated, the dolls returned to human form.

Unfortunately, shortly after Judai defeated Camulla, Fubuki's body was too drained from having the power of Darkness inside of it for so long, and he died.

Some effects were immediate: Asuka was removed from Duel Academy due to her parents' fears that they might lose their other child.  Samejima resigned from his role as Principal as a way of taking the fall so that the school didn't have to, leaving Chronos as the new one in his place.  Daitoukuji, meanwhile, not only resigned from his position as the alchemy professor, but also from his position on the Seven Stars – he had been willing to experiment on students in order to extend his life, but he drew the line at others dying so that he could live.  As a result of his decision, his body turned to dust and he died himself, without telling any of the students the truth about how he had been the seventh Star, or even where he had hidden his key.  Kagemaru, the leader of the Seven Stars, then began to search for a replacement, but it was in vain, and before he could find one, he also passed away of his old age.

Fairly soon after that, Manjoume's brothers decided that they wanted to purchase Duel Academy because, since they had determined that their youngest brother was unable to become the top of the Duel Monsters world, they would do so instead.  The conditions set up by Kaiba Seto, however, were that in order to purchase the school, the purchaser would have to defeat a student at the school who was using a deck of monsters that had less than five hundred attack points.  Their choice for an opponent was, obviously, their youngest brother.

Ojama Yellow was the only card of his that met the conditions, but some of the third-year students offered up a rumor of a well where the cards that duelists threw away because they were too weak went.  Rumor had it that this well was filled with their vengeful spirits, unhappy to have been simply tossed aside like that, but Manjoume went anyway.

This was how he met Ojamas Green and Black – they were in the well and asked if Manjoume knew who had thrown them down there, complaining that they missed their brother.  Yellow then appeared and was reunited with his brothers at last, and Manjoume decided that he would take in all of the cards that had been thrown into the well.  After all, he kind of had to, really, if Duel Academy was to be saved from his brothers.

Manjoume won that duel against Chousaku, even though he didn't use any monsters that had a single attack point, and he learned two valuable lessons.  The one that he admitted to was that he had learned how to deal with being considered at the bottom.  The one that he did not, at least aloud, was that he had learned that even the weakest cards could be powerful in the right situations.  From that day onward, in fact, he played a deck that combined powerful, evolving dragons with his Ojamas and support spells for them.

Taniya, the fourth Star, attacked, and Judai defeated her after Misawa failed.  Manjoume defeated the Black Scorpions and their leader, Don Zaloog, while Judai defeated Abidos, and Sho, who had been given Asuka's key when she left, showed how much he had improved and defeated Titan.

The remaining holders of the keys – Judai, Sho, and Manjoume – waited expectantly for the seventh of the Stars to show their face and attack.  However, months passed, and not a word of the seventh reached any of their ears.  It began to seem unlikely that the seventh was even coming, but this could be a new tactic, to catch them off their guard.  So even as their second year of school dawned, they continued to protect the keys, waiting for their final enemy to appear.

Little did they know that he actually would appear – in Saiou Takuma. 

Due to a small interpretation error, Manjoume remained in the Osiris Red dormitory, though he was qualified to return to Obelisk Blue.  A duelist from the Pro Leagues, Edo Phoenix, defeated Judai in a duel, and because his manager, the aforementioned Saiou Takuma, was a psychic who had taken an interest in Judai and wanted to control the power that he had hidden inside of him, Saiou had laced Edo's final attack with his power.  This was enough to cause Judai to lose the ability to see the images on his cards, though not enough to bring him under Saiou's control.

Due to this, Judai left the island.  While Judai was away, Saiou came to the island, trying to find a different duelist to suit his purposes because his initial plan hadn't worked out.  And when he came across Manjoume, they dueled.

Manjoume lost that duel, but not before Saiou had played his share of mind games with him.  For a while now, Manjoume had seen Judai as a rival, someone he had to grow strong enough to defeat… but lately, he'd also been seeing him slightly as a friend, and these conflicting feelings had created an inner confusion that he usually had tried to ignore, but Saiou brought to the forefront.  This was how Saiou's power reached him, by taking advantage of his confusion and promising that he could become strong enough to defeat Judai if he stopped looking at him as a friend and relied on Saiou's power.

After this, Manjoume began wearing only white clothing and talking about an association for those who had been embraced by the Light – the Hikari no Kessha. 

There was a second significance to this result, however – the key that Manjoume had carried now technically belonged to Saiou.  And when he asked what it was, the now blindly-loyal young man explained about the three demon cards, and Saiou officially made it his goal to obtain the seven keys.  Three of them were already placed in their slots, and all it took for them to become officially his was for him to win them from someone who carried them in a duel – the brainwashed Manjoume happily obliged.

At first, most everyone just shrugged Manjoume off as having finally gone off the deep end.  But then, he started dueling everyone in the Obelisk Blue dormitory... and every student that lost to him became brainwashed by Saiou's power into joining the aforementioned cult.  He had dyed most of the Obelisk Blue dormitory white, and even a bit of Ra Yellow, when Sho decided that enough was enough and faced him in a duel to try and knock him to his senses.

Sho lost to Manjoume and joined the Hikari no Kessha.  It wasn't due to any lack of skill on his part; it was mostly due to mind games – due to Saiou's power augmenting Manjoume's taunts, Sho became convinced that the only way he would ever be worthy of being related to his brother was to become stronger, and the Kessha could let him do that.  With his loss, Saiou gained another key, and Judai lost one of his most important friends.  Because of this, combined with the guilt he felt for being the one to defeat Darkness and, therefore in his mind, deal the final blow that killed Fubuki, Judai began to believe that anything he tried to do to try to change this situation would do nothing but harm things.  He was so scarred, in fact, that he was unable to defeat the now-white Sho when he was challenged, and though he did not become brainwashed himself because of his own hidden powers, he lost his own key.

This duel between Judai and Sho took place at the same time as a duel between Manjoume and Misawa, which ended in Misawa joining the Hikari no Kessha and Manjoume tossing his Ojama cards to the wind.

Incidentally, because Samejima was no longer the Principal, there was no Genex tournament.  Therefore, there was no reason for Prince Ojin to come to Duel Academy, and no opportunity for Saiou to obtain the keys to SORA.  However, that would no longer be needed, if Saiou was capable of obtaining the final key… but then again, that seemed a nearly impossible task.  Daitoukuji had hidden it well – even Saiou himself admitted that it was quite possible that only the spirits of the island would be able to locate it.  And somehow, the exposure to the powers of the Light had removed Manjoume's ability to see duel spirits.

And so it went.  Judai and a few of the students and teachers who had managed somehow to resist the Light's influence on the island were rumored to have formed an underground resistance group, though Judai was willing to do little for fear that he would mess things up even more than they already were.  Edo attempted to defeat the Light that was possessing Saiou in a duel, but he failed and became brainwashed as well.  The entire island seemed surrounded in an aura of Light energy, almost choking to those who hadn't been exposed to it and either assimilated or proven immune.  The island's administration wound up with its hands tied – Chronos would very much have liked to have contacted the proper authorities to bring help to the island, but there were hundreds of students in the Hikari no Kessha, thanks to Manjoume, and only one of him.

And so, the third year commenced.  There was an exchange program announced – four students and a teacher from the various dueling academies around the world were to attend Duel Academy for a semester.  Chronos had tried to convince Professor Cobra that now wasn't the best time, but Cobra was very insistent.

In order to provide the best welcome they could, Chronos decided that he would have a famous Japanese artist hold a concert on the island the first night that the exchange students were there – Cobra had suggested a duel instead, and it would have made sense, but Chronos wanted to avoid exposing the exchange students to the Hikari no Kessha if possible.  And so, he hired an up-and-coming voice in the business, a young woman who went by the stage name of Asuryn, to perform.

Saiou soon got wind of this plan and decided to use it to his own means.  Asuryn would be spending about a week on the island before the concert – during that time, Manjoume would show her around, keep her company, do what she wanted him to do for her, stuff like that, and slowly – slowly – convince her to join the Hikari no Kessha.  This woman was no duelist, after all, and therefore could not be convinced through cards, and more… drastic measures would risk damaging her charisma and popularity. 

Once she was a member, she would use her music to spread the Light's influence to all those who listened to her voice, not just duelists.  She had already made it onto the top singles charts several times, so it was obvious she had a large fan base, even for being young and relatively new to the field, so the message would spread quickly.  …At least, so went the plan.

So the week before the concert was supposed to happen, Manjoume met the boat that came to Duel Academy… only to discover that the idol Asuryn was actually Tenjoin Asuka, who had chosen to take a singing route in memory of her brother when her parents had forbidden her from continuing to follow any career involving dueling.

Manjoume did as he had been asked to by Saiou – he accompanied her around the school, showed her all the things that had changed, told her about everything that had happened while she had been away, and most importantly of all, kept her company.  However, after three days of this, it became obvious that the result would not be how Saiou had anticipated – somehow, Asuka remained unaffected by the Light's power that was spread throughout the island, while Manjoume was beginning to have doubts about his own affiliation with the Hikari no Kessha. 

Why did he have such faith in the Light, anyway?  What had it ever done for him, really?  He hadn't gotten to defeat Judai yet – in fact, with every passing day that goal seemed more and more pointless, the other less and less willing to duel with all of his strength.  He had wanted to become strong enough to defeat Judai himself, not weaken his resolve for an easy win!  And furthermore, there was something about Asuka that he had never noticed when she was at Duel Academy.  Now that he was talking with her more often, he was beginning to see how brilliant a person she really was, even without being one with the Light.  If someone that amazing existed outside the Light, then what truth was there to the Light's superiority to everything?

The fact that Asuka hadn't converted yet failed to escape Saiou's notice, and during one of his daily readings, he discovered that the Sun (which he had previously read as a card representing Asuka – providing assurance and brilliance to whichever side she happened to support) and the Moon (he had no way of knowing who or what this could represent; however, whatever it was, it seemed to have caused someone – possibly Asuka – painful emotions that would not go away) were connected to the Tower (or the destruction of all that he had sought to accomplish with the Hikari no Kessha).

Deciding that drastic measures were now unavoidable, Saiou ordered Manjoume to bring Asuka to him so that he could expose her to the Light's full power and convert her that way.  However, rather than being the ever-willing brainwashed servant, Manjoume actually argued against Saiou's order, unwilling to let her get hurt.  After all, hadn't that been Saiou's original intention?

As punishment for his insubordination, Saiou used his full power and overwhelmed Manjoume's mind, draining all of his free will from him.  And so, no longer in control of his thoughts or actions, Manjoume brought Asuka to Saiou, who tied her to a wall and used his full power to attempt to reach her mind.

…Only it still didn't work as Saiou had planned – all it did was cause her intense pain, and the Light still didn't reach her mind.  She went into a bit of delirium from the pain, calling her deceased brother's name as if in a vain attempt to beg for help from him.

Manjoume, still not in control of his actions, stood there, blankly watching on.  Something inside of him began to hurt as well though… the longer he watched, the more of Asuka's suffering he saw and heard, and the more his heart began to awaken and decide that he really should do something to stop it.

Soon, Asuka began to call out not only Fubuki's name, but Manjoume's as well.  It was a simple request for forgiveness for whatever it was she had done to him that he would get so upset that he would bring her here, to this torture. 

The breaking point for Manjoume was when she begged him to help her, calling not his family name as most people usually had, but his given name, Jun.

Somehow, hearing that one simple word was all that Manjoume needed in order to break free of all of the enchantments that Saiou had placed upon him.  He remembered everything he had done during that time, and his first feeling was one of utter revulsion at how he, the great Manjoume Thunder, had stooped so low as to serve a guy like Saiou, and to do all of those things.  He could see clearly now – everything Saiou had promised had been a lie.  How had he not seen that before… how could he have listened to him like that? 

But he forced himself to focus on the matter at hand first before yelling at himself – first, he needed to free Asuka.  Saiou had no time to react as Manjoume's leg swiftly kicked him in his back, knocking the wind out of him and causing him to collapse to the ground… and more importantly, to lose focus on Asuka.  It was a simple matter from there for Manjoume to open the clasps that bound Asuka to the wall and – since she had fallen unconscious from the shock – carry her away to the one place on the island where he knew the two of them would be safe.

The infirmary was specifically neutral ground – Ayukawa Emi, the nurse, gym teacher, and head of the Girls' Dormitory, was adamant about that.  No one fought there, and members of both the Kessha and the (ever-shrinking) resistance group were permitted there to get treatment for any injuries or diseases that they would happen to get.

Not that there were many injuries.  Usually, if fights broke out, they were duels.

Judai happened to be there as well – he had tripped and sprained his ankle, and so Tyranno Kenzan, rumored to have not been converted even having lost to Saiou himself in a duel thanks to a piece of a dinosaur bone buried in his leg, had brought him so that he could recover.  Not that he was in much danger, being more or less immune to the Light's influence, but it was still better for him to be in neutral space while he couldn't run.  Manjoume made an attempt to ignore him, sickened by what he'd been reduced to due to his delusions that, somehow, everything was his fault.  (While, of course, denying the fact that he felt exactly the same way about himself.)

It became a bit difficult to ignore him later that night, however.  Asuka was asleep on a hospital bed next to Judai's, and she wasn't going to wake up until morning at the earliest, or so Ayukawa had said.  And yet, Judai was talking to someone – Manjoume couldn't tell who – who was at least in the general direction of Asuka's bed, and it was apparently a human someone, judging by the boy's tone.

When Manjoume asked who he was talking to, Judai looked at him strangely and wondered aloud if he had lost his ability to see spirits.  After all, sitting on Asuka's bed was the spirit of her brother, Fubuki, who had been haunting the Swing of Memories – a particularly special card between the two of them that he had asked Ayukawa to give her before he died – ever since Asuka had set foot on the island again.  And, of course, having unwillingly been taken over by the power of Darkness for so long, he kept a bit of it inside of his soul, and had been using it to protect Asuka from being overcome by the Light's influence.  …Or at least, Judai claimed that Fubuki was there, and that he had said that.  Not that Manjoume was particularly inclined to believe him.

The next morning, after Manjoume had changed into one of his (much more comfortable) black uniforms, Asuka woke up.  After the two boys managed to explain things to her, and after a heartfelt apology from Manjoume, the three of them decided that the best course of action would be to try to find the last of the keys, the one that Daitoukuji had hidden.  Finding the final key would allow them to make sure that Saiou couldn't get his hands on the demons, and possibly give a plausible reason to challenge him.  However, Manjoume, in his stubbornness, was unwilling to work with Judai, believing that he would just get in the way, and Judai also expressed his unwillingness to duel.

By this time, the other members of Judai's resistance group had arrived.  It was tinier than even Manjoume had expected – the only ones left were Judai himself, Kenzan, Momoe, Junko, and Kabayama (the head of the Ra Yellow dormitory).  Kenzan was furious to see Manjoume there, and he tried to convince Asuka to leave him behind, that he was untrustworthy, and that the only way to defeat Saiou and save everything would be to come with them.  But she declined, stating that Manjoume had saved her life, and so she wouldn't leave him behind.

As the resistance group left, Manjoume and Asuka decided that it would still be the best course of action to attempt to find the final key, even if it was just the two of them.  The only question was where to start looking.  Saiou had once told Manjoume that it was likely only the spirits on the island would know where it was, and though he didn't want to admit that any of what he had done had happened in the first place, he did bring up that possibility – and his former ability to see spirits – with Asuka, who formed a plan.  If Manjoume could no longer talk to spirits himself, and they needed to do so in order to find the key, why not talk with one a different way?

After all, communication like that – specifically, the usage of Ouija boards – wasn't unheard of at the Academy: back in their first year, Takadera – another Obelisk student – and his friends had attempted to use one.  With mildly disastrous consequences, but that didn't mean that rumors that it had been done hadn't circulated.

And so, they decided that the best way to proceed was to go to the library and attempt to find a book detailing spiritual communication.  Asuka would search through the books herself while Manjoume stood guard outside – it was likely that Saiou had members of the Hikari no Kessha looking for them, and Manjoume could at least defend himself and make enough time for Asuka to escape.

While Asuka searched through the library, Manjoume found himself accidentally drawn into a duel.  The entire Hikari no Kessha, by this point, had learned of Manjoume's betrayal, and they had, as expected, been given orders to bring him and Asuka to Saiou if found.  And who should come across Manjoume but Misawa, who the now-black-jacketed student had converted personally.

And would un-convert personally as well – this duel between Manjoume and Misawa was a rather quick one, which Manjoume won.  In fact, by the time Asuka emerged from the library with the necessary book, there were hardly any signs that any duel had been performed at all, save a white coat having been hastily thrown to the ground.  (Just the coat, mind you.)

They decided to contact the spirits in the one place that no one connected to the Light would ever think to look – the Abandoned Dormitory.  So many rituals connected to darkness had occurred there (though the two of their combined knowledge only knew for sure of what Titan had done) that the place was nearly tainted with the stuff.  The Light's power would certainly shy away.

It was a full moon that night, providing just enough light for the two of them to see by in the Abandoned Dormitory's lobby.  They set up their makeshift Ouija board – a piece of paper with the proper markings in the proper places and a coin to use as a marker – and called forth the spirits of the island to ask them where they would find the seventh key.

What they did not realize until it was too late, however, was the fact that it was really only the basement of the dormitory that was infected with darkness, and the Light's power still managed to get into the lobby and interfere with the reading.  With their heightened level of connection to all things spiritual, if nothing was done, the two of them would have easily fallen to the Light's influence.

Would have, except that at the last second, Asuka pulled Manjoume's and her own hand away from the board and fled to said basement, dragging a mildly stunned Manjoume along with her.

When they were safely in the basement and certain that the Light wouldn't follow them, it became apparent that Asuka wasn't herself.  In fact, she had been possessed – by the ghost of her older brother, Fubuki (naturally proving that Judai had been right).  Through her, he told Manjoume the true location of the final key – it was in a specific clearing in the forest, not notable except for a single small boulder in the center.  The key would be found with its lanyard encircling the bottom of the rock, though it would be hard to spot.

After promising Fubuki that he would do what he could to protect Asuka from the material dangers that the Light's power held (while Fubuki protected both of them from the intangible ones – ever since Manjoume had broken free of the Light's influence with his own power, he had been under Fubuki's protection, which prevented him from succumbing again), the deceased young man left, leaving his sister unconscious, in need of rest.

And so, after making sure that there was no way anyone would come down to surprise them, Manjoume fell asleep while sitting against the wall, next to Asuka.  Rest was a good idea, and they both needed it.

Not that he would wake up there, but…