Agnes Tachyon: The Superluminal Princess of Tracen Academy

The Day She Arrived

Agnes Tachyon walks through the iron gates of Tracen Academy on a warm spring morning, a white lab coat draped over her uniform, two glowing test tubes clinking at her side. Every trainer on the courtyard turns to look. She doesn’t look back. She comes from a distinguished lineage of elite horse girls and has been designated her family’s “crowning achievement.” But she has zero interest in being anyone’s crown jewel. She has one reason for being here — to unlock the absolute upper limit of how fast a horse girl can run, and she will burn every rule in the handbook to do it.

The academy’s administration already knows her name. They know what she is capable of. She performs all manner of experiments on living subjects — unauthorized, dangerous experiments, at that. Symboli Rudolph, watching from the window of the student council office, sighs and immediately makes a phone call. She arranges for Agnes Tachyon to share quarters near Manhattan Cafe. Someone needs to keep an eye on her.

Tachyon sets down her bag in her assigned room, looks around once, and immediately begins converting the adjacent storage room into a laboratory. By nightfall, unknown liquids are bubbling, chalk equations cover three walls, and a faint purple glow leaks under the door.

The Guinea Pig Trainer

In her first meeting with her trainer, Tachyon uniquely refers to him as “guinea pig” and immediately subjects him to a variety of experiments. The trainer, confused and slightly alarmed, sits in a metal chair surrounded by measuring equipment while Tachyon circles him with a clipboard.

“Your cardiovascular response time is… disappointing,” she announces cheerfully. “But workable. You’ll do.”
The trainer opens his mouth to protest. Tachyon hands him a test tube filled with glowing amber liquid. He looks at it. She smiles. She loves to treat her trainer to unusual tea in test tubes, usually glowing and suspicious-looking.

He drinks it. He immediately regrets it.

She views the trainer as both an experimental subject and an assistant, requiring him to take care of her daily life. This means grocery runs, picking up her lab coat from the floor, reminding her that meals exist, and occasionally standing very still while she attaches sensors to his wrists to measure “baseline anxiety in non-horse-girl organisms

The trainer quickly realizes there is no escape. He also realizes, slowly, that she genuinely trusts him — in her own terrifying way.

Manhattan Cafe and the Haunted Lab

The room was originally going to be used by Manhattan Cafe alone, but at the same time, Tachyon was looking for a space to use as a laboratory, and it is said that Symboli Rudolph put the two together to keep watch over Tachyon, who was causing trouble.

Manhattan Cafe, soft-spoken and ethereal, floats into the shared space one evening and finds Tachyon drilling holes in the ceiling to hang vials of luminescent fluid. Cafe stares. Tachyon waves a wrench without looking up.

“Ah, Cafe. Good timing. Hold this.”

Cafe holds a beaker of shimmering purple liquid with both hands, staring at it like it might whisper her fortune. It does, in fact, briefly make a sound. She screams. The beaker doesn’t break. Tachyon is pleased.

The two have made an abandoned classroom a shared hangout space. Despite their differences, they both care for one another. Tachyon scrawls incomprehensible equations on one wall while Cafe pins pressed flowers and handwritten fortunes on the other. Somehow it works.

Cafe is the only person Tachyon doesn’t refer to with the “-kun” suffix, showcasing that Tachyon has a unique level of respect for her. Cafe is also the only person who can intimidate Tachyon.

One afternoon, Tachyon tries to sneak a new experimental serum into Cafe’s tea. Cafe turns around. She does not say a word. She only stares. Tachyon slowly lowers the dropper.

“…On second thought, the control sample is more useful.”

The Air Shakur Rivalry

Air Shakur and Tachyon are often paired together due to both of them having high intelligence — Shakur being a technological prodigy, and Tachyon being a mad scientist. Although the two share an interest in science and data, their approaches clash. Shakur derides Tachyon’s romanticism while Tachyon believes Shakur’s pragmatism is lacking in potential. Tachyon likes to provoke Shakur.

Air Shakur stands at the whiteboard in an empty classroom, writing clean lines of optimized data equations. Tachyon leans in the doorway, arms crossed, smirking.

“Your math is technically correct,” Tachyon says.

Shakur doesn’t turn around. “But?”

“But technically correct is the least interesting kind of correct.”

Shakur grips the chalk harder.

In one incident, Tachyon makes an offer to Air Shakur, who is struggling with calculations during an experiment, to join her experiment, and in return, she agrees to join Shakur’s experiment. Thanks to this, there are strange scenes where Tachyon, who always drives others crazy with her strange experiments, is involved in Shakur’s experiment herself and suffers.

Shakur’s experiment involves precise timed intervals and carefully calibrated machines. Tachyon lasts fourteen minutes before she starts trying to “improve” the equipment mid-run. A minor explosion follows. Both of them are covered in blue powder. Neither one acknowledges the other for the rest of the day.

At dinner, they sit two seats apart and both pretend it never happened.

The Silence Suzuka Incident

One afternoon, Agnes Tachyon stands at the training track fence and watches Silence Suzuka run. She doesn’t move for a long time.

She becomes fascinated by the running of Silence Suzuka. She kidnaps the trainer of Team Sirius, interrogating him to test his skills. She warns the trainer about Suzuka’s risky speed, offering advice based on her scientific insight.

The Team Sirius trainer is sitting in a chair with a bright light shining in their face, three notepads in front of Tachyon, and what appears to be a heart rate monitor clipped to their ear.

“She is running at a speed that her body has not fully calculated the consequences of,” Tachyon says flatly. “I am not telling you this because I have feelings about it. I am telling you because the data is concerning and you seem like the type who needs facts stated clearly.”

The trainer stares at her.

“Also,” she adds, “your reaction time is slightly above average. Not worth studying, but not embarrassing.”

Later, she applauds Suzuka for breaking her limits in the Japan Autumn Grand Prix — the Tenno Sho. Tachyon watches from the stands alone. When Suzuka crosses the finish line, Tachyon claps once, slowly, and writes something in her notebook. Nobody sees what it says. Later, Cafe finds a single pressed four-leaf clover tucked inside that page.

Tachyon denies putting it there.

Plan A, Plan B, and the Problem With Her Legs

Late one night, the trainer finds Tachyon sitting at her lab desk, not experimenting, not writing. Just sitting. The bubbling machines are all turned off. The room is quiet for the first time in weeks.

“You know,” the trainer says carefully, “you don’t have to run if it’s dangerous.”

Tachyon doesn’t look up. “Every experiment carries risk. That is what makes the data meaningful.”

“That’s not what I asked.”

A long pause.

“My legs,” she says quietly, “are the one variable I cannot fully control. Everything else in this world — speed, time, the reaction of compounds, the stride patterns of forty different horse girls — I can account for. My own legs remain… inconvenient.”

She picks up her pen. She starts writing again. The machines hum back to life.

The trainer stays in the doorway for a while, then quietly goes to bring her something to eat. She has almost no interest in common sense behavior or daily life, and prefers to let others like her trainer handle her food and clothes. She doesn’t say thank you. She does eat every bit of it.

The Drop-Out That Never Happened

Cafe gets concerned for Tachyon when she tries to drop out of Tracen Academy.

It happens on a Tuesday. A stack of resignation papers appear on the headmistress’s desk. Tachyon’s signature is at the bottom. No explanation. No prior warning.

Cafe finds out through the rumor network that travels at horse-girl speed through the dormitory halls. She is at Tachyon’s lab door in under four minutes.

She doesn’t knock. She opens the door. Tachyon is packing vials into a crate, her back turned.

“If you leave,” Cafe says very quietly, “who is going to make me hold dangerous things at 11 PM?”

Tachyon keeps packing.

“Who is going to fill my side of the room with chalk dust and claim it’s ‘particle residue’?”

More packing.

“Agnes.”

Tachyon stops.

Cafe never uses her first name.

Tachyon stands there with a vial in each hand, looking at the wall. After a long moment she sets them down. She doesn’t explain why she was going to leave. She doesn’t explain why she stays. She just starts unpacking the crate, slowly, and puts everything back exactly where it was.

The Sugar Tower

Agnes Tachyon has great speed, smartness, and natural talent as a runner. However, her legs are fragile and could break at any time, making racing dangerous for her. To solve this, she works on many “Plans” — like Plan A, reinforcing her own body.

Tachyon’s favorite food is black tea, and her SR support card even depicts her building a tower out of sugar cubes and putting them in her black tea. According to calculations, at least 59 sugar cubes can be confirmed, amounting to 1180 calories from sugar alone.

On any given Sunday morning in the shared room, Tachyon sits cross-legged on her chair, stacking sugar cubes into a precise architectural structure while her black tea steams beside her. Manhattan Cafe watches from across the table, fortune cards fanned in her hands.

“That is not how tea works,” Cafe observes.

“Everything is how tea works if you commit to it,” Tachyon replies, placing cube number forty-seven with surgical focus.

Air Shakur walks past the open door, glances in, and keeps walking without a word.

The tower reaches sixty-one cubes before Tachyon drops all of them into the cup at once. The splash ruins two pages of Cafe’s notebook. Tachyon declares the experiment a full success. Cafe dries her notes in silence with the practiced patience of someone who has been through this before.

What the Research Really Means

The trainer finds Tachyon’s personal notebook once — not the lab notebook full of equations, but a smaller one, plain black cover, tucked under a stack of reference manuals.

He only reads one line before closing it. He never mentions it.

The line reads: “If the limit of speed cannot be reached in one lifetime, then the research must matter more than the runner.”

He places the notebook back exactly as he found it. That evening, when Tachyon hands him a test tube of glowing green tea with the casual authority of someone who has never once questioned whether he will take it, he takes it without hesitation.

She watches him with those sharp amber eyes, unreadable as always.

“Your trust levels have improved significantly since we began,” she announces.

“Is that a compliment?” he asks.

“It’s data,” she says. Then, quietly: “But yes.”