I Am Writing a Diary in a Crossover Manga

9 AM—Dorobiga Park opens its gates.

On weekends, there were already large crowds queuing at the entrance, eager to buy tickets.

[Dear guests, thank you for your patience. The park is now open. Please enter in an orderly manner.]

As soon as the announcement was made, the crowd surged forward, filling the amusement park with energy and excitement.

Most attractions had already been prepared to handle the massive influx of visitors, ensuring smooth operations.

However, the food vendors weren't as immediately popular.

After all, amusement park tickets were already expensive, and since most visitors had just eaten breakfast before arriving, the food stalls wouldn't see peak business until about an hour after opening.

Shortly after the park opened, many costumed staff members could be seen distributing flyers and balloons along the main walkways.

Naturally, Amamiya Ren was one of them.

"Excuse me, may I have a balloon?"

Hearing a soft, refined voice behind him, Amamiya Ren quickly turned around. With practiced efficiency, he grabbed a balloon and handed it toward the source of the voice.

Through the limited field of vision of his mascot costume, he saw a young girl dressed in a deep purple kimono.

Her long, silky purple hair was styled in an elegant princess cut, and her voice carried a delicate, noble tone—soft and sweet, like a lady from an aristocratic family.

Even though her kimono was relatively simple in design, it looked incredibly expensive.

"Thank you."

The little girl accepted the balloon with perfect manners, making Amamiya Ren develop a good impression of her.

Polite children were always well-liked, no matter where they were.

As he watched her turn and disappear into the crowd, he resumed his work.

The girl with purple hair made her way through the bustling park, eventually arriving at a hidden, private lounge area designated for VIPs.

"Miss Isumi, this way please."

"Understood."

Inside, Saginomiya Isumi spotted a familiar face and immediately brightened up.

"Nagi!"

"You're here, Isumi."

Sanzenin Nagi, already seated comfortably, happily reached out to pull her friend down onto the couch beside her.

"So, Isumi—did you notice anything strange about that man?"

"Yes, something does feel… off."

Recalling her brief interaction with him, Isumi nodded seriously.

His aura was deathly still, yet he showed no signs of actually dying. Three malevolent spirits clung to him, yet none of them attacked him. This contradiction was highly unusual.

But there was something else Isumi couldn't understand.

"Nagi, how did you even find this person?"

"Hehe~"

Sanzenin Nagi giggled mischievously and lifted a diary that was invisible to everyone else.

"Actually, it's because I have this—a diary only I can see. And inside, I can read entries written by that man."

Hearing this, a flicker of intrigue flashed in Isumi's deep purple eyes.

A powerful surge of spiritual energy gathered in her gaze as she attempted to pierce through the diary's concealment…

But even with her abilities, the object remained completely invisible.

"So, Nagi has encountered something beyond my spiritual perception?"

Unlike Maria, Isumi fully believed in Nagi's words. If Nagi said she possessed a mysterious diary, then Isumi had no reason to doubt her.

And considering the odd aura surrounding that man, it was clear that Nagi's interest wasn't unfounded.

"Otherwise, there's no way she'd know about him in the first place."

With this realization, Isumi leaned in closer, taking the matter even more seriously.

"So, Nagi, your plan is to observe his actions today and compare them with the entries in his diary to check for inconsistencies?"

Sanzenin Nagi beamed.

"Exactly!"

"He mentioned two names in his diary before—Shido Masayoshi and Akechi Goro. Apparently, he tried to search for them but confirmed that they don't exist in this world."

"He also wrote that our world is just a 'story'—but at the same time, he acknowledged its reality."

"I see… so that's why you're so intrigued by him?"

Isumi pondered for a moment.

She couldn't confirm whether his words were true or false, but she knew Nagi loved topics like this.

Turning her attention back to the live surveillance feed showing the mascot performer, Isumi's expression sharpened.

"Regardless, Nagi-chan, I think you may have found something truly unusual this time."

"So… are you planning to stay here and monitor him all day?"

"Of course not!"

Sanzenin Nagi immediately waved her hand in rejection.

How could someone as impatient as her just sit around watching a screen all day?

"Isumi, you, Maria, and I are going to the amusement park instead. We'll have fun while keeping an eye on him. Let Claude handle the surveillance."

"???"

Claude, who had been standing silently behind them, was instantly filled with question marks.

"Miss, but what about your safety? And Miss Isumi's?"

"Maria will handle it, of course. Don't worry, she's much stronger than you think. Honestly, I wouldn't be surprised if Maria knew some kind of assassination martial arts. Do you think just anyone can get close to us?"

Hearing herself randomly assigned combat expertise, Maria felt her blood pressure rise.

"Why does an ordinary maid like me suddenly know assassination techniques?!"

But considering Nagi's personality, arguing was pointless.

With a long-suffering sigh, Maria gave a subtle glance to the surrounding bodyguards, signaling them to discreetly follow.

The well-trained guards immediately understood.

As professional bodyguards, they wouldn't be negligent, no matter what their young mistress believed.

Meanwhile, at the Park Entrance…

Just as Nagi and Isumi were preparing for their "stealth mission", two more high-society young ladies arrived outside Dorobiga Park.

"!"

The moment their car doors opened, both girls stepped out at the exact same time.

And the instant they saw each other—

They both noticed the same expression of shock written on each other's faces.

As if neither had expected the other to be here.

"Long time no see, Miss Suzuki."

A black-haired girl with a cold, frosty demeanor spoke first.

Her tone was polite, yet unmistakably distant.

"You, of all people, still have a childlike side? You actually go to an amusement park on weekends?"

The brown-haired girl facing her wore an expression of exasperation, looking as if she were dealing with something truly exhausting.

"To be honest, you're the last person I wanted to run into today."

Because every time they talked, she felt like she was conversing with a frozen porcelain doll—expressionless, emotionless, utterly unreadable.