I was Reincarnated as the Scum Older Brother of the Protagonist in a Romance Battle Game, But I don't want to Die, so I'll do my Best - Chapter 1 Secret Realm Test Arc

I slowly opened my eyes to an unfamiliar ceiling…

Turning my head, I saw unfamiliar furniture, unfamiliar wallpaper, and an unfamiliar desk…

And on that desk—a photo frame.

……Am I still dreaming? I thought, closing my eyes again. But I didn’t feel like I could fall back asleep, so reluctantly, I sat up, glanced around the room, and slowly stood before picking up the photo frame that had caught my attention.

At first glance, everything had seemed unfamiliar, but as I took a closer look at the people in the photo…

“…This is Miyashita Airu and Kitano Joji, right…?”

In the photo was a woman with long, pink, wavy hair and large scarlet eyes. Her nose was elegantly straight, complemented by delicate lips, and her skin was so translucent it looked like a work of art. Even through her school uniform, her figure was undeniably stunning. Yet, her expression was unnaturally blank.

Next to her stood a man with neatly styled, slicked-back red hair and sharp, narrow black eyes. He was tall—180 cm—with a slender build, and he wore his uniform with stylish flair. Objectively speaking, he was undeniably handsome. But his lecherous gaze was fixed on Airu’s chest, and the smirk twisting his lips radiated nothing but malice…

These two were the main heroine of the school romance supernatural battle game Demon Capital Tokyo 1999, Miyashita Aru, and…

…the trashy, weak villain character who gets utterly destroyed by the protagonist early in the story before fading into obscurity, only to be mentioned in a single line during the ending credits as “deceased”—the protagonist’s older brother, Kitano Joji.

A bad feeling crept over me. With trembling hands, I opened the wardrobe beside the desk. Inside hung several flashy outfits that screamed “villain,” along with a few neatly pressed school uniforms. I pulled one out.

Emblazoned on the br3ast pocket of the blazer was the school emblem—a logo combining the kanji for “East” (東) and “Light” (光), stamped like a seal.

I recognized it. No—I only recognized it.

“This… is the uniform of Tōkō High School, the setting of Mato 99 (short for Demon Capital Tokyo 1999), right…?”

Then, hesitantly, I turned toward the mirror attached to the inside of the wardrobe door—

“…What the hell? This is Kitano Joji.”

I touched my face, confirming the sensation as I stared into the mirror.

“Does this mean… I’ve been reincarnated into the game? And of all people… as Kitano Joji?”

Despair washed over me as my reflection’s refined features twisted in disgust. Why, of all characters—

“Out of everyone, I had to become the character I hate the most in Mato 99.”

◆

Demon Capital Tokyo 1999 is a school romance supernatural battle game set in a fictional Tokyo high school.

The premise is as follows:

In 1999, a massive tectonic shift caused an ancient ruin—known as the Kamiiishi (God Stone)—to emerge at the base of Mount Fuji, acting as a counterpart to the Ama-no-Iwato (Heavenly Rock Cave) from Japanese mythology.

As a result, people across the country began to perceive the gods of myth—the Yaoyorozu no Kamigami (Eight Million Gods)—as described in the Nihon Shoki and other regional legends. By communicating and forming contracts with these gods, humans gained supernatural abilities—

Some could wield fire, others lightning. Some could summon wind or rain—powers straight out of myth itself.

But as people gained the ability to interact with gods, mysterious dungeons known as hikyou (Secret Realms) began appearing across the land. These realms served as bridges between the divine domain (shin’iki) and the human world (jinin), but they were also dangerous places teeming with monsters and false gods (gishin).

Those who braved these realms and reached the divine domain could negotiate with the gods, receiving their blessings. Some gained greater power, others extended lifespans beyond human limits, and some even attained the status of divine agents.

As word spread, people began researching ways to challenge these Secret Realms, developing a training regimen known as gyō (Discipline). This allowed them to efficiently hone their ability to communicate with gods—Kamishi (Divine Sight).

Eventually, gyō became a standard subject in schools, deeply ingrained in daily life.

Then, in 2010, a meteorite fell into Tokyo Bay.

Research teams discovered that the meteorite contained divine energy rivaling even the God Stone. However, no one could perceive a god within it. Deeming it dangerous, the government sealed it deep underground in a secure facility.

Eighteen years later, the story begins in 2028.

The protagonist, Kitano Takeru, grew up in an orphanage in Hokkaido, having lost his parents at a young age. However, his innate talent for Kamishi caught the attention of the prestigious Kitano family, who adopted him.

Bound by duty to serve the family, he trained rigorously in gyō. One day, his adoptive brother—the biological son of the Kitano family—Kitano Joji, began bullying him. Meanwhile, Joji’s fiancée, Miyashita Airu, confided in Takeru about the sexual harassment and abuse she suffered from Joji.

Takeru listened earnestly, offering her comfort. Eventually, pushed to her limit, Airu publicly annulled her engagement with Joji in front of the entire school. Humiliated and enraged, Joji punched Takeru in the face, leading to a formal duel witnessed by the Kitano family.

The difference in skill was obvious—Takeru, blessed with talent and hardened by discipline, effortlessly crushed Joji, who had coasted on his family’s name without putting in any effort.

Incidentally, this duel also served as the game’s early combat tutorial, ending in just three turns.

Joji’s disgraceful behavior, his pitiful performance in the duel, and the fact that the Kitano family’s guardian deity—a kitsune god—sided with Takeru led the family to disown Joji, officially naming Takeru as the heir.

Takeru grew closer to Airu as her new fiancé, and together with friends he made at school, he conquered Secret Realms across the land.

Eventually, he attained divine power great enough to confront the final boss—Kos-Tartart, an otherworldly god that emerged from the meteorite—saving the world in the process.

While the main story followed a classic hero’s journey, Mato 99 was packed with hidden content—sub-heroine routes, secret endings, and even a true final boss. The sheer volume of extra content, easily double the length of the main story, was the game’s true appeal.

And now, I had been reincarnated as that trashy, weak villain who fades away early in the story—Kitano Joji.

Judging by the color of the uniform’s necktie, the current timeline was the start of the second-year semester—the very beginning of the story. And in this very semester, I was destined to lose pathetically to the protagonist in the tutorial and vanish from the narrative.

“This is the worst… I’ve barely reincarnated, and my death flag is already raised…”

This is the story of a man who was reincarnated as the weak, trashy villain meant to disappear early in a school romance supernatural battle game. Using his knowledge of the game, he struggles desperately to avoid his death flags—while somehow managing to pick up all the sub-heroine’s flags along the way.