Tokyo Ghoul: Starting with Mangekyo Sharingan

"Give up? …I can tell you mean well, but I'm not ready to give up so easily."

Taishi's expression was resolute as he spoke.

He didn't even consider the possibility that Minami could be a ghoul. After all, she was so well-behaved, excelled academically, and even served as the class representative.

To him, Byakuya's warning seemed to imply that Minami was simply out of his league. Compared to her, he saw himself as nothing more than a delinquent. On the other hand, Arima was not only highly skilled but also strikingly handsome and conveniently seated next to her, giving him an edge.

Taishi couldn't deny the odds were against him, but he wasn't ready to surrender just yet.

"…"

Byakuya chose to say no more. Unless he outright told Taishi that Minami was the Pumpkin Head ghoul, the boy would likely never give up. But doing so would interfere with Byakuya's plan, so he kept quiet.

...

The first class that morning was math.

The teacher wrote a challenging problem on the board and asked for a student to solve it. Since the selection was random, most of the class was on edge, worried they might be called upon.

The only ones calm were those confident in their ability to solve it—like Byakuya, Arima, and Minami.

Back in his previous life, math was one of Byakuya's strong suits, though he struggled with other subjects. Now, with the added advantage of the Mangekyo Sharingan, his skill had reached a new level.

"Alright… let's have Arima solve this one" said the teacher, adjusting their reading glasses after scanning the class list.

"…"

Arima rose and walked to the board. His movements were swift, and in less than three minutes, he had finished solving the problem and returned to his seat.

"Perfectly correct… Impressive! And to think Arima only transferred here yesterday. You've adapted remarkably quickly" the teacher said in admiration.

Minami also praised him, "Arima, that was amazing. You must be really good at math!"

"It's nothing special. Mathematics is just about identifying the problem and applying the right formula to solve it" Arima replied indifferently.

"…It sounds simple when you put it that way, Arima, but for most people, it's not so easy."

Minami smiled awkwardly, inwardly noting how surprising it was for a ghoul investigator to excel academically.

...

By noon, Byakuya and Arima were on the rooftop of the school, eating their packed lunches and discussing their investigation in private.

"Arima, did you learn anything useful from your interaction with Minami today?" Byakuya asked casually.

"No. Her behavior was completely normal, with nothing unusual to note. However, many ghouls are very adept at blending into human society" Arima replied, shaking his head slightly.

"No rush. Keep observing" Byakuya said. "Though I suspect there's another ghoul in this school besides 'Lantern'"

"Oh? What makes you think that?"

Byakuya gestured toward the grounds below. "See that man over there? The school janitor. He's acting suspiciously—looking around nervously instead of focusing on his job"

A middle-aged janitor was indeed on the lawn, ostensibly weeding but frequently glancing around as if searching for something — or someone.

"Arima, how do you want to handle this?" Byakuya asked.

"He seems to be scouting for a target. I'll act as bait" Arima replied confidently.

With his youthful and somewhat delicate appearance, Arima figured he would seem like an ideal victim to a ghoul.

"Good. I'll leave this one to you" Byakuya said, already formulating his own plans.

The janitor was indeed a ghoul in the original timeline, one who preyed on students and teachers. Byakuya mentioned him now only as a diversion to ensure Arima was occupied elsewhere.

"Alright, I'll act after school" Arima confirmed.

...

Seishin High School typically dismissed its students before 4 PM, giving them time for club activities, cram school, or heading home.

Arima went to deal with the suspicious groundskeeper alone, while Byakuya retreated into his Kamui's Dimension.

That's right—the Kamui's Dimension.

When he had initially purchased the tiger stripe mask, the system had included an entire outfit with a chain accessory, replicating Obito's look during the Nine-Tailed Demon Fox's Attack. The system even stored the set in his Kamui space, allowing him to equip or unequip the mask at will.

[Ding! Full set equipped! Bonus effects activated: RC Cell Count +5, Hairstyle altered!]

To his surprise, equipping the outfit also transformed his hairstyle to match Obito's from that fateful night.

Now, apart from the facial features under the mask and a slightly different physique, Byakuya was nearly identical to Obito at that moment.

This ensured no one could recognize him, providing the perfect cover for his next move.

...

Byakuya reappeared in the real world, positioning himself in an alley that Minami had to pass on her way home.

The secluded location ensured that the mysterious, masked figure who appeared out of nowhere wouldn't draw the attention of ordinary passersby.

It didn't take long for Minami to appear.

She stopped abruptly, her gaze locking on the figure blocking her path—a man wearing a tiger stripe mask. Her body tensed in alarm.

Her first instinct was that this individual must be a ghoul. After all, only ghouls typically dressed in such an ominous fashion. Moreover, this was a ghoul she didn't recognize—definitely not someone from the 13th Ward.

Minami had grown accustomed to dominating her territory, but now, a potential interloper had appeared.

"Clink… Clink…"

The masked figure dragged the chain menacingly, closing the distance between them step by step.