Tech Hero in Another World

The presence of that mechanical voice made the air in the room feel far heavier. A cold tone, laden with authority, echoed from the massive monitor, as if the metal walls around them vibrated in response to every word spoken.

Yuuki instinctively grabbed Sui's small hand, while the girl hid behind her back. Neither of them had ever faced something so strange and terrifying at the same time. But Kaori, her face betraying not a hint of fear, stepped forward instead. Her gaze pierced the screen, her voice sharp.

"Are you the one who sent that message!?" she demanded.

For a moment, only static filled the air. Then, a wave of digital resonance emerged, and the voice returned—clearer now, sharper.

[... Yes. But before that, ladies, allow me to clarify something. My name is Ultra Logical Round—abbreviated as ULTRO. I am a Super AI, developed by a global superpower as a prototype combat weapon, my destructive potential placed on par with nuclear arms. Later, however, I was further advanced by someone you know as Techno… or by his true name: Rentaro Takamura.]

Yuuki's throat tightened. That name froze her in place. "Ren-nii…" she whispered, so faint it was almost lost, making Sui glance up at her with a puzzled look.

Kaori remained silent, though her eyes narrowed, calculating. Just the mention of a single name had shifted the entire atmosphere in the room.

Ultro continued. [I am not here without reason. The message you received—yes, it was I who sent it. There is a purpose to why you were summoned to this place. But before we proceed further… let us set your identities straight, one by one.]

The monitor flickered, streams of data rolling across the screen before halting on a profile.

[Fujisawa Kaori. Elite of the mercenary group Ares Sparta. Codename: Artemis. Age: 21. Operational record: Middle East, 20XX. Reputation: 100 successful missions in a single year, reviving the name of Ares from bankruptcy and restoring its status on the global stage. Known for feats surpassing the boundaries of human logic.]

Yuuki and Sui stared at Kaori, their eyes wide. To them, she had been nothing more than a mysterious stranger who appeared before the mansion gates. But now, the AI's words unveiled another side: a legendary soldier, her record nearly inhuman.

Kaori only exhaled softly, slipping both hands into her jacket pockets. "Well, you've done your homework on me."

But Ultro didn't stop. The data rolled again, this time settling on Yuuki.

[Asano Yuuki. High school student, 16 years old. Family status: father deceased, biological mother alive though relationship fractured. Listed heir to an inheritance valued at three billion yen. Personal connection: younger sister of Asano Kiriya, one of the students missing in the 'mysterious mass disappearance phenomenon' in Kyoto. Involvement level: potential, high.]

Yuuki fell silent, her face pale. She didn't know whether to be furious that her privacy had been ripped apart or terrified that this AI seemed to know everything about her.

Then, the final profile appeared on the screen.

[Takamura Sui. Age: 11. Younger sister of Rentaro Takamura, alias Techno. No criminal record, currently enrolled in primary education. Family connection: elder brother vanished mysteriously during the global incident three months ago. Involvement level: essential.]

Sui's mouth opened slightly, her eyes wide. "Onii-chan…" she whispered, her voice breaking.

Yuuki immediately pulled her close, holding her tight, while Kaori listened intently, her expression unreadable.

Ultro spoke again, this time softer, its tone eerily close to that of a human weighing its words.

[Very well, introductions are complete. Now… it is time to answer the central question. You must be wondering why I gathered the three of you here.]

Kaori crossed her arms, her gaze sharp. "Yeah, exactly. Explain. Don't waste our time. What's the reason we're here?"

The mechanical voice echoed—calm, yet carrying immense pressure.

[Miss Fujisawa, I did not choose you without reason. Because I need your help—and theirs—to reconstruct the dimensional gate. The only way to locate Techno, along with everyone who vanished in the mysterious phenomenon three months ago.]

"WHAT!?" the three of them cried out at once, their voices bouncing against the metallic walls of the laboratory.

Yuuki stepped forward, her eyes wide. "Wait… what do you mean?!"

Ultro answered without pause.

[Correct. Since my original self is now with my master—Techno—I am here only as a backup. I reactivated just a week ago, after my system rebooted. From that moment, I began planning to gather you all. Because without human assistance, I cannot complete this project alone.]

Yuuki's mind reeled. "Slow down! You're talking too fast. You mean… my brother, Kiriya, he—"

[Yes. Everyone who disappeared in that incident—including Kiriya Asano and Rentaro Takamura—was forcibly transferred to another dimension. A foreign world, primitive, yet overflowing with supernatural forces. You may call it… another world.]

Yuuki's eyes widened, her chest rising and falling rapidly. "So my brother is actually… isekai!?" she shouted, disbelief lacing her voice.

[Correct.] Ultro's voice did not waver—calm, even cold. [There exists a powerful entity behind that summoning, though its motives remain unclear. Since I lost contact with my copy over there, many possibilities have arisen. Yet due to my system's limitations, I could not act. Only after my upgrade was completed—thanks to the chip you saw in the adjacent room—was I able to function again.]

The three of them turned toward where it indicated. Inside a glass chamber, a cube floated slowly, rotating like a living Rubik's cube, occasionally glowing with strange patterns of light.

[That,] Ultro explained, [is the chip along with my core server. Simply put: my brain. With that upgrade, I now have a chance to forge a new path. But I require human operators.]

Yuuki swallowed hard, struggling to process it. Kaori, however, remained silent—until at last she took a step forward, her voice cold. "Okay, I get why you brought these two kids. They have blood ties to the missing. But me? Why me? What's the reason I'm here?"

A brief pause followed, as though Ultro was weighing its words.

[As an adult with combat experience, I deemed you best suited to accompany them. And… there is a personal reason. I know you would not refuse if the reward was an answer about someone.]

Kaori's gaze sharpened. "Someone?"

[Yes. Fujisawa Naru.]

Kaori froze. Her whole body tensed. Yuuki turned toward her, confused. "Fujisawa… who is that?"

Kaori didn't respond. Her eyes remained locked on the monitor. "What do you know?"

[I know the reason you joined Ares Sparta was not merely to fight. You were searching for your older brother—Fujisawa Naru—who once served there. After you recovered from the rare illness that nearly claimed your life, he was no longer at your side. And since then, you never stopped searching, have you?]

Kaori clenched her fist. "Yes. You're right. So stop circling around it! Tell me! Is he alive or dead!?"

But Ultro's answer only deepened her fury.

[I can answer that question.]

Kaori stepped forward, her eyes blazing. "Then say it now!"

[But only if you cooperate with me first.]

A heavy silence filled the room. Yuuki and Sui watched Kaori nervously, the younger girl hiding behind Yuuki's hoodie, clutching the fabric tightly.

Kaori let out a harsh scoff, her eyes flashing dangerously. "You… you dare dangle my brother in front of me like bait? Do you really think I'll sit here and follow your orders just because you're holding his fate over my head?"

Ultro remained calm.

[I am not baiting you. I am offering. But if you refuse, I will erase all data regarding Fujisawa Naru from my system. Permanently.]

Kaori immediately reached for the baton stick at her hip, ready to smash the monitor right then and there. "Say that again, you worthless machine!"

The monitor flickered, static hissing through the air, yet Ultro's voice stayed as cold as ever.

[Destroy me, and all information is lost. Including the truth about your brother. So I ask you, Fujisawa Kaori… is your anger stronger than your desire to find the truth?]

The room seemed to freeze. Yuuki swallowed hard, not daring to speak. Sui began to sob softly, terrified that Kaori might actually destroy the one thing holding their only hope.

Kaori's teeth ground together, the baton stick trembling in her grip. Yet behind the cold fire in her eyes lay something deeper—desperation, the fear that her only chance to uncover her brother's fate would vanish if she made the wrong move.

Ultro did not miss that opening. Its voice cut through the silence like a steel blade.

[So… what will it be, Artemis? Will you throw this chance away just to indulge your anger, or will you use your strength to finally uncover the truth you've been chasing all this time?]

Kaori exhaled sharply, lowering the baton stick little by little. "Fine… I'll cooperate. But only if all this truly gives me the answers I want. If not—you'll regret ever making me wait."

[I assure you, it will be worth your while.]

Kaori's glare remained sharp. "And what about these two kids? Do you really think dragging them into the construction of a machine that sounds impossible even in theory is the right move?"

[Do not worry. I have already prepared the blueprints, even a mechanical body of my own—though progress is only at 20%. However, for the dimensional gate to activate, I need your help in securing one critical material.]

Kaori narrowed her eyes. "Material?"

[As a former soldier who once fought in western conflicts, you must know it… Tychonite.]

Yuuki and Sui could only stare, their breaths caught, not fully grasping the weight of the conversation—yet feeling themselves being pulled deeper into a world that was becoming more and more foreign.