Shichen had a dream—an incredibly long one.
In the dream, he had just graduated from college, still carrying that youthful innocence. He dared to save someone, but an accident happened.
He didn't die. Instead, he arrived in a "two-dimensional" world and began crossing paths with them.
He knew who they were; they didn't know him. With that information advantage, he easily built connections, and those connections kept deepening.
The first person Shichen met was Kato Megumi, then Kasumigaoka Utaha and Eriri. They were classmates, and Megumi was even in his class.
Seeing the girls he loved—girls he'd once only been able to watch from behind the barrier of fiction—Shichen couldn't stay indifferent. He approached them, built rapport, helped them fulfill their wishes, and lingered in that ambiguous, not-quite-defined closeness.
He followed a certain "someone's" path—made it into a "game," gathered them together, lived alongside them day after day.
Every day was nonstop chaos.
The only difference was that he was greedier. He wouldn't choose just one.
Being with them made him forget time, forget himself. He thought he'd only ended up in the Saekano world.
Then one day, he ran into a terror incident—and met Nishikigi Chisato, a girl he couldn't forget after a single glance.
Soon after came Inoue Takina.
He wanted to meet them. He threw himself into the terror incident, kept helping them, and his relationship with them grew closer and closer.
Shichen had a system. By helping them, he could raise his abilities—both everyday skills and combat abilities.
He didn't think too hard about why he had a system. He treated it as a transmigrator's cheat. With his youthful mindset still intact, in the world he'd dreamed of for so long, he only had one thing: endless pursuit.
To become better. To become reliable.
Then he was found by a certain existence.
It claimed to be the will of the world, and it needed his help to protect this world.
It didn't explain how to protect it—because Shichen was still too weak.
So, to make him stronger, it would let him go to other worlds to obtain power.
Other worlds? Shichen agreed without hesitation. If the world he'd longed for could be invaded, he would have stepped up even without being asked.
After all—he was already here.
The first world he went to was Strike the Blood.
He entered the school as a student, became friends with Akatsuki Kojou, and joined their small circle.
He knew a lot, but he didn't have the power to help Aiba Asagi—he couldn't save her biological mother. All he could do was stay quietly by her side.
His relationship with Asagi kept getting better.
Then Aurora was found.
He had come to this world to gain power, so he followed Kojou and his sister as they left Itogami Island.
They thought their father had simply called them for a trip—nothing serious—so they brought Shichen along.
Shichen used a bit of "foreknowledge" to win Kojou's approval and successfully tagged along.
After that, he became Aurora's Blood Servant.
And through shadowy arrangements by certain organizations, he became the Fourth Primogenitor.
Then he became entangled with Natsuki Minamiya.
Shichen wasn't like Kojou, someone anyone could push around. After gaining tremendous power, he became forceful and imposing, determined to build his own empire.
Because of his relationship with Asagi, some people misunderstood him—and started "arranging" cute girls around him.
And since his True Ancestor power hadn't fully awakened yet, he also needed a medium's blood anyway.
He met Himeragi Yukina, met Kirasaka Sayaka.
He crossed paths with La Folia, and saved Kanon.
More and more girls gathered around him.
After his power fully awakened, he built his own Night Empire.
The second world was Konosuba.
In that world, he "tempted" Aqua shortly after she descended to the human realm, met Megumin and Yunyun, and clicked with Darkness. He formed an adventuring party with them.
He wasn't heartless either—he even gave Satou Kazuma some money so Kazuma could live comfortably.
In that world he learned many skills, many spells, and grew stronger.
Konosuba's power system really was absurd compared to other worlds—skills and magic could be learned freely as long as you could level up. It was basically like grinding mobs in a game.
Shichen was already strong, not some rookie. Leveling was easy.
And as the Fourth Primogenitor with vast, nearly limitless magic, that system was like wings on a tiger.
Reputation, status—he gained everything in that world.
The third world was Fate.
Its biggest benefit to him was "bathing" in the Holy Grail—materializing the soul and obtaining infinite magical energy.
With his abilities, he could have steamrolled the Holy Grail War. But how could he pass up the chance to meet King Arthur?
And he wasn't one of the seven Masters at first.
Shichen didn't hesitate. He took Kiritsugu Emiya's Command Seals and became Artoria's Master.
At first, they got along poorly—almost like enemies.
Which was normal: Artoria was the King of Knights, noble and just. How could she accept someone like Shichen who had seized that position?
But as they spent time together and grew familiar, she realized how good he was to her—like he understood her, knew everything, always acted for her sake.
He even took her on dates, treated her to good food, and let her enjoy modern life.
Her feelings gradually became conflicted.
Then the Holy Grail War ended.
What she hadn't expected was that Shichen came from another world—and he'd joined the Grail War to deal with the "All the World's Evils" inside the Lesser Grail.
Her wish couldn't be granted.
After the war ended, Shichen left alone—without taking Artoria with him.
Artoria didn't disappear either. She remained in the modern world and helped protect Matou Sakura.
Shichen didn't dare move recklessly and change history. Though he saved Sakura, he still left her in the Matou household—for the sake of ten years later.
With Artoria by Sakura's side, he didn't need to worry about her safety.
Shichen didn't leave that world either. He went to a different timeline—one with a different kind of Holy Grail War.
Not seven separate camps, but 7 vs 7, two great factions.
There, Shichen met the girl Jeanne d'Arc.
Jeanne's purity and her great love moved him deeply—and his possessiveness reached a level it had never reached before.
After that war ended, he took Jeanne with him.
Jeanne didn't resist. Her love was so vast that she accepted Shichen's selfishness and chose to accompany him.
Because she saw it: even though he seemed fine on the surface, deep down he was profoundly lonely.
She needed to stay with him.
Then she experienced the unbelievable:
There were other worlds.
And they were wildly different.
Jeanne witnessed many things—and changed a lot.
The fourth world was Date A Live.
Shichen didn't arrive at the story's beginning, but five years before it.
He knew everything, so he saved Itsuka Kotori, saved Origami Tobiichi, and from "Phantom" he guessed at what he himself had done.
He found Tokisaki Kurumi and used her power to alter history.
He met the First Spirit, but because Kurumi's spiritual power was insufficient, he returned early.
History still repeated itself.
But what needed to be done was done.
After that, he began meeting Yatogami Tohka in that world, and helped Takamiya Mio clean up the mess.
Because of Kurumi, Shichen began studying the difference between spiritual power and magic power, and fused the two.
As the Fourth Primogenitor, all he needed to do was devour and assimilate.
Everyone's power—plus Mio's world-creating power—was fused into one within him.
He reached a strength beyond anything he'd known.
The fifth world was Re:Zero.
He met Natsuki Subaru, crossed paths with Emilia, and helped Rem find her way.
He became Emilia's knight, accompanied her through the royal selection, defeated the other candidates, and helped her gain the people's support.
Emilia eventually became queen.
In that world, he came to understand divine protections, understood Authorities, and fully integrated that knowledge.
At last, he touched the origin of the world.
The world's will was the will of all worlds—the god of this dimension.
But even a dimensional god had enemies it couldn't defeat.
That enemy was Outer Evil.
Some loved this dimension; others hated it.
All kinds of negative emotions merged into one, invading and destroying this world.
The world's will couldn't resist—this was a difference in dimension. It simply wasn't a match.
That was why it reached out to Shichen—someone from a higher dimension.
And it didn't choose randomly.
It had seen Shichen's kindness: risking his life to save someone.
That selfless act.
So it chose him.