Chapter Summaries

Yinsen and his companions established identities and settled into late-twentieth-century Britain while waiting for Hogwarts admission notices. When the letters arrived, Professor McGonagall visited to explain the school to the children and their guardians, prompting Yinsen to wonder whether Dumbledore had noticed him.

• Yinsen arranged Logan's British identity using records created in North America, and the group entered the Harry Potter world six months before Harry's admission notice.
• The group adapted to their roles and identities, with Selene acting as guardian to several children and Rin Tohsaka questioning why she had been adopted.
• Hogwarts owls delivered admission notices to the group, whose letters listed supplies but gave no directions to Diagon Alley.
• Selene answered a visit from Minerva McGonagall, who explained that she had come because an unusual number of new students from ordinary families had gathered together.
• Yinsen observed McGonagall with magic and wondered whether Dumbledore had noticed his supposed talent, before learning she suspected a possible conspiracy.

Professor McGonagall met Yinsen and the other children, then secretly watched over them as Selene took them to Diagon Alley. Yinsen and Illya explored the crowded street before meeting the others at Ollivanders Wand Shop, where Illya asked whether magic required a wand.

• Professor McGonagall questioned Selene, met Yinsen and the other children, and told Selene how to reach Diagon Alley and exchange money.
• Professor McGonagall secretly followed Selene and the children to Diagon Alley, leaving only after they entered.
• Selene went to Gringotts while Yinsen and the others split up to explore Diagon Alley.
• Yinsen and Illya wandered the shops, and Illya received treats from vendors that became lunch for both of them.
• Yinsen and Illya arrived late at Ollivanders Wand Shop, where Illya asked whether magic required a wand and Yinsen explained that wands only assisted spellcasting.

Yinsen and Illya chose wands at Ollivanders, where Yinsen selected one for its appearance and demonstrated his control over its power. After shopping in Diagon Alley, Yinsen found Illya crouched beside a white bear cub.

• Yinsen and Illya arrived at Ollivanders after the rest of the group had chosen their wands, and Ollivander brought them wands to try.
• Yinsen explained how wands guided and amplified magic, then asked Ollivander to find him the best-looking wand.
• Yinsen chose a Yew Wood wand with a Fireball Dragon Dragon Heartstring core and controlled its power without trouble.
• Illya tried several wands before choosing a Palm Wood wand with a Phoenix Feather core.
• Yinsen greeted Harry Potter outside the shop, then continued shopping with the team, who decided they did not need to buy pets.
• Yinsen found Illya crouched in a corner, staring at a white bear cub.

Yinsen and his companions traveled to Hogwarts, where they met Hermione and joined the new students’ Sorting Ceremony. The chapter ended with Yinsen being assigned to Slytherin, while his companions were sorted into the other Houses.

• Illya bought a white bear cub and named it Little White during the group’s trip through Diagon Alley.
• Yinsen and his companions boarded the Hogwarts Express, where Hermione asked whether they had seen Neville’s missing toad.
• Leah and Rin joined Hermione in searching the train compartments, and the three girls became friends.
• Hagrid led the students to Hogwarts, where Professor McGonagall explained the Sorting Ceremony.
• Hermione, Ron, and Harry were sorted into Gryffindor; Leah went to Hufflepuff, Scáthach to Ravenclaw, and Rin and Logan to Gryffindor.
• The Sorting Hat assigned Yinsen to Slytherin.

Yinsen was sorted into Slytherin despite coming from a Muggle family, prompting curiosity and prejudice from his new Housemates. As Hogwarts's opening feast began, he studied Dumbledore's food-summoning magic and confirmed that this world's magic was the kind he wanted to learn.

• Yinsen wondered why the Sorting Hat had placed him in Slytherin, while Draco Malfoy introduced himself and reacted with disbelief when Yinsen said his family was ordinary and Muggle.
• Daphne Greengrass, Astoria Greengrass, Pansy Parkinson, and other Pure-blood students kept their distance, while a Half-blood upperclassman welcomed Yinsen and said Slytherins would accept him if he proved his abilities.
• At the Gryffindor table, Rin Tohsaka and Hermione discussed Yinsen's origins and power, and Harry and Ron noticed him sitting alone among the Slytherins.
• Dumbledore ended the Sorting Ceremony and conjured a feast, while Hermione and Rin wondered whether Yinsen could change Houses.
• Yinsen examined the magic that produced the food and concluded that Hogwarts's magic was conceptual and rule-based.

Yinsen began studying magic at Hogwarts after settling into Slytherin, where his diligence and unusual talent quickly won Snape’s approval. After Draco Malfoy tried to confront him, Yinsen left Malfoy sprawled in a hallway overnight, and Malfoy stopped picking fights with him.

• Illya explained that Snape and McGonagall had allowed her to keep Little White at Hogwarts, though the bear cub was given a separate place to live.
• Gemma Farley showed the new Slytherins their common room and explained its password rules before sending them to bed.
• The next morning, Yinsen traded insults with Draco Malfoy, but Gemma interrupted before Malfoy and his lackeys could attack him.
• Yinsen began studying magic in McGonagall’s class and spent extra time investigating how spells worked, while still learning faster than most students.
• Snape came to appreciate Yinsen’s diligence and talent, while Malfoy continued to resent the attention Yinsen received.
• After Malfoy cornered Yinsen in a hallway, he ended up lying on the stone floor all night and stopped provoking him.

Yinsen watched the Philosopher’s Stone plot begin on Halloween as Harry Potter, Ron Weasley, Hermione, Rin Tohsaka, and Scáthach slipped away to investigate the troll. The next day, he found Rin injured in the hospital wing, and she blamed her bad luck.

• Yinsen advised Rin Tohsaka through a Mental Link to relax and guide magic rather than trying to control it, helping her understand why spellcasting felt awkward.
• At the Halloween feast, Yinsen realized Professor Quirrell was likely beginning his attempt to steal the Philosopher’s Stone.
• Harry Potter and Ron Weasley slipped away from the students, and Hermione and Rin Tohsaka followed them while Scáthach went after the group too.
• Yinsen led Illya after the Slytherins instead of joining the troll encounter, reasoning that Scáthach would keep the others safe.
• The next day, Yinsen visited Rin Tohsaka in the hospital wing and found her leg wrapped up; she explained her injury by saying she had bad luck.

After visiting the injured Rin Tohsaka, Yinsen followed Scáthach into the forbidden room containing the Three-Headed Dog. Dumbledore caught them and sent them away, but Scáthach discovered a secret door beneath the dog and planned to return.

• Yinsen visited Rin Tohsaka in the infirmary after the troll broke her leg, then left when she seemed to be recovering.
• Yinsen encountered Scáthach exploring Hogwarts, and she persuaded him to join her search for the Restricted Section.
• Yinsen opened the locked door, and Scáthach circled the sleeping Three-Headed Dog while Yinsen followed her inside.
• Dumbledore appeared, told them students were forbidden from entering, and escorted them out without punishing them.
• Scáthach told Yinsen that a secret door lay beneath the Three-Headed Dog and suggested they return; the dog had fainted in fright when they entered.

Yinsen watched Harry Potter, Ron Weasley, Hermione Granger, and Rin Tohsaka get drawn into the Philosopher’s Stone plot, while Scáthach noticed that Yinsen had not grown at all since arriving in this world. He considered ways to disguise his unchanged appearance, leaving his future growth unresolved.

• Scáthach teased Yinsen during their nighttime wanderings and watched Harry Potter and his companions visit Hagrid’s hut.
• Yinsen recognized that Harry, Ron, Hermione, and Rin were moving toward the Philosopher’s Stone plot and reflected that Harry’s intervention gave Voldemort a chance to reach the stone.
• After Draco Malfoy reported them to Professor McGonagall, Harry, Ron, Hermione, Rin, and Draco lost fifty House Points each and received additional punishment.
• Yinsen dismissed the idea of correcting Harry’s personality and wondered whether Dumbledore cared about Harry’s fate beyond defeating Voldemort.
• Scáthach pointed out that Yinsen had not grown in more than a year, and Yinsen said he might use magic to change his appearance if his body remained unchanged.

Yinsen collected a sample of unicorn blood in the Forbidden Forest while Harry and the others faced danger there, but he avoided getting involved. As he and Scáthach returned toward Hogwarts, Yinsen considered investigating the Philosopher's Stone for help with his own situation.

• Yinsen noticed that Illya had barely grown despite her body becoming that of a normal human, and decided to keep watching her development.
• Filch took Harry and the others to Hagrid for detention patrolling the Forbidden Forest, where Yinsen remembered Voldemort had been attacking unicorns.
• Yinsen teleported into the Forbidden Forest with Scáthach and collected a sample of unicorn blood while following Hagrid's group.
• Scáthach went to watch Harry's encounter with Voldemort, but Yinsen left the forest and refused to get involved.
• Yinsen and Scáthach discussed his cautious approach to strength and her progress restoring Rune Magic as they headed back toward the castle.
• Yinsen wondered whether the Philosopher's Stone could help with the problem troubling him.

Yinsen followed Harry Potter’s path to the Philosopher’s Stone with Scáthach, while Draco Malfoy secretly tailed them and joined their descent. They reached the enchanted chess room, where Yinsen saw Rin Tohsaka with Harry and Ron.

• Yinsen decided to follow Harry Potter and his friends quietly, but noticed Draco Malfoy was tailing him.
• Yinsen met Scáthach, and they entered the fourth-floor room after Harry’s group; Scáthach calmed Fluffy and fed the Three-Headed Dog before they jumped into the trapdoor.
• Yinsen and Scáthach escaped the Devil’s Snare, then freed Malfoy with a burst of light when he became trapped in the vines.
• Malfoy followed Yinsen and Scáthach past the Winged Keys after Yinsen unlocked the door with magic.
• Yinsen reached the chess room and found Ron Weasley and Harry Potter playing with Rin Tohsaka among their group.

Yinsen intervened in the Chess Game trial to protect Ron and clear the path, then confronted Quirrell at the Mirror of Erised. The chapter ended with Voldemort emerging and realizing Yinsen already held the Philosopher’s Stone.

• Ron sacrificed his knight to set up Harry’s checkmate, but Yinsen destroyed the opposing Queen before it could capture him.
• Yinsen blasted the chess pieces blocking the way aside, allowing Harry, Ron, Hermione, Rin Tohsaka, and the others to continue.
• Harry learned from Quirrell that Quirrell had tried to kill him during the Quidditch Match and that Snape had actually been protecting him.
• Yinsen stopped Harry from obeying Quirrell and called him a thief trying to steal from the school.
• Voldemort emerged from Quirrell’s turban and saw Yinsen examining the Philosopher’s Stone.

Yinsen took the Philosopher's Stone from the Mirror of Erised, and Harry's touch destroyed Quirrell while Voldemort escaped as smoke. Yinsen handed the stone to Hermione, and Dumbledore revealed himself to the children.

• Yinsen retrieved the Philosopher's Stone from the Mirror of Erised, baffling everyone except Scáthach.
• Quirrell charged at Yinsen, but Yinsen shoved Harry into him, and Harry's protective magic caused Quirrell to crumble into ash.
• Voldemort emerged from Quirrell's remains as black smoke and lunged at Harry, but Yinsen pulled Harry out of the way, allowing Voldemort to flee.
• Yinsen studied the Philosopher's Stone and extracted some of its magical power while Hermione urged him to give it to Dumbledore.
• Yinsen tossed the Philosopher's Stone to Hermione, and Dumbledore appeared before the children.

After Dumbledore recovered the Philosopher’s Stone, Harry and his friends received public credit while Yinsen’s role stayed hidden. As the school year ended, Yinsen reunited with his companions and wondered how to spend Summer Vacation.

• Dumbledore took the Philosopher’s Stone from Hermione, praised Harry and his companions, and noted Yinsen’s wandless, nonverbal spell that had saved Harry.
• At the House Cup ceremony, Dumbledore awarded Gryffindor enough points to beat Slytherin, while the school heard that Harry had thwarted Professor Quirrell and protected the Stone; Yinsen’s part remained secret.
• Malfoy complained that Harry had received the spotlight, but Yinsen declined to explain his suspicions about Dumbledore’s plans for Harry.
• Yinsen’s first year at Hogwarts ended, and he packed to leave for Summer Vacation, regretting that he could not stay and study in the library.
• Yinsen reunited with Logan, Leah, Scáthach, Illya, and Rin Tohsaka, heard about their school year, and considered finding another world to spend the vacation.

Yinsen returned to Britain for the summer and balanced an ordinary-child routine with trips to other worlds. He sent Soujun on his first reincarnation mission to YuYu Hakusho, where Soujun planned to learn spirit energy and grow stronger.

• On the train, Yinsen worried about how to spend the summer, while Hermione asked about his sour mood and discussed studying during the holidays.
• Selene picked up Yinsen and the others, told him Evelyn, Jonathan, and O'Connell were traveling around Britain, and warned that he might be watched.
• Yinsen spent his days acting like an ordinary child and his nights visiting other worlds to handle affairs, including checking on Artoria and Shirou Emiya and giving Soujun the tools he had made.
• Yinsen told Soujun to choose his first reincarnation world and focus on surviving and getting stronger, and Soujun chose YuYu Hakusho to pursue spirit energy and possibly become Genkai's disciple.
• Yinsen used Teleportation Magic to send Soujun to YuYu Hakusho without preparing anything for him.

Yinsen gave the others modified phones with a game based on the Fate world, prompting Rin Tohsaka and Illya to consider whether it depicted a parallel version of their reality. During a quiet summer of gaming and training, the group grew stronger, and Rin and Illya ended the chapter arguing over their game pulls after a sparring match.

• Yinsen gave the group phones that could access an ordinary world's internet and introduced them to Fate/Grand Order before its launch.
• Illya, Rin Tohsaka, and Scáthach began playing after the game launched, while Selene and Leah joined and Logan chose to listen to music.
• Rin wondered whether the game described a parallel version of their world, and Yinsen suggested she already knew the answer.
• Yinsen taught Leah advanced subjects and sparring, while Scáthach and Logan also helped train Leah, Illya, and Rin.
• After Illya injured Rin during a sparring session, Rin accused her of being jealous over her game summon and vowed to make the producer add Berserker to the gacha pool.

Yinsen prepared for Harry Potter’s second year while considering whether to interfere with Harry’s life, but Illya pulled him away from Selene to ask for game currency and reassurance about the Fate story she had watched. Illya fell asleep holding Yinsen’s clothes, and Rin Tohsaka explained that she understood why Illya needed him nearby.

• Yinsen reviewed the events of Harry Potter’s second year and wondered whether Dumbledore had deliberately shaped Harry’s difficult upbringing.
• Yinsen considered rescuing Harry from his relatives, but Illya interrupted him and Selene by pounding on Selene’s door.
• Illya asked Yinsen to top up her game account, and he told her he would arrange a way to make online purchases on a future visit.
• Illya asked whether she would suffer the fate she had seen in the anime and learned that Heracles had originally been meant to become her Servant.
• Illya asked Yinsen to kill Gilgamesh for her, declared Berserker the best, and fell asleep clutching Yinsen’s clothes.
• Rin Tohsaka told Yinsen she understood Illya’s need for someone she trusted and reflected that her own life had diverged from the story she once watched.

After a summer of training, Rin Tohsaka and Yinsen’s group returned to Hogwarts with Hermione Granger. Yinsen noticed Harry Potter and Ron Weasley approaching by flying car and, remembering the Chamber of Secrets events ahead, asked Hermione if she liked snake meat.

• Rin Tohsaka reflected on her rapid progress in magic and combat after training with Yinsen, Illya, Leah, and Scáthach.
• Yinsen and the others met Hermione Granger at the station, where she wondered why their parents were absent and mistook Selene for Yinsen’s mother.
• Hermione noticed that Yinsen had not grown since the previous year, and he brushed off her concern as being a late bloomer.
• Yinsen sensed Harry Potter and Ron Weasley traveling beside the train in the Weasleys’ Flying Car after Dobby blocked them from entering the platform.
• Yinsen recalled that the Chamber of Secrets would open and Hermione would be petrified, then asked her whether she liked eating snake meat.

Yinsen and the others returned to Hogwarts for their second school year, where Gilderoy Lohart’s useless Defense Against the Dark Arts lessons and a confrontation between the Quidditch teams passed without major trouble. The peace ended when Mrs. Norris was petrified, and Yinsen watched the investigation while confirming that Illya could undo the condition.

• Yinsen discussed the Chamber Serpent’s deadly gaze and venom with Logan, while Hermione chatted with Rin Tohsaka about magic studies.
• At the start-of-year feast, Albus Dumbledore introduced Gilderoy Lohart as the new Defense Against the Dark Arts professor.
• Yinsen handed Lohart a blank test, then knocked away Pixies during a chaotic lesson while Hermione brought them under control.
• Yinsen’s presence stopped Draco Malfoy from insulting Hermione, preventing Ron Weasley from retaliating with his broken wand.
• After Mrs. Norris was petrified and Harry Potter became a suspect, Yinsen examined the cat as Illya said she could undo the petrification.

While researching how to stew a snake, Yinsen was drawn into Harry and Ron’s search for the Chamber of Secrets. With Scáthach’s help, they found its entrance, and Dumbledore decided to enter with Snape, Harry, and Yinsen.

• Yinsen rejected Harry and Ron’s suspicion that Draco Malfoy was the Heir of Slytherin and agreed to help them find the Chamber of Secrets.
• Yinsen sent for Scáthach, who identified a hidden passage beneath a sink in the abandoned girls’ bathroom.
• Harry found a Serpent Marking on the faucet and used Parseltongue to open the entrance, confirming it led to the Chamber of Secrets.
• The professors gathered at the bathroom entrance, and Dumbledore chose to enter with Snape, Harry, and Yinsen.