"Life is an experiment, and we its guinea pigs. You, me, the other Umamusume—everyone!" -Agnes Tachyon

Equal parts researcher and runner, Agnes Tachyon pursues the limits of speed with the power of science. She will stop at nothing to quench her pure thirst for knowledge, performing all manner of experiments on living subjects—unauthorized, dangerous experiments, at that. Her extreme tunnel vision means that without someone to support her, day-to-day necessities quickly fall to the wayside.

She is not willing to sacrifice any time for other activities, such as cooking or training. Tachyon is also very excited and determined about her scientific experiments

Agnes Tachyon is a short, young girl, who also has fair skin, and short, messy brown hair with a prominent ahoge bent backwards at an odd angle with horse ears. Also has red eyes with conspicuously missing "eyeshine" that are 'marked' with, strange, horizontal grid-like patterns. Tachyon also wears a single earring on her right horse ear in the shape of the chemical structure of indane. Tachyon's most salient trait is her long lab coat, worn as part of her racing outfit. This labcoat has so-called "moe sleeves" running past her fingers, as well as striped patches on the upper sleeves. The hip section of the coat is adorned, and detailed with two pairs of 'throwing bandoliers' filled with corked test tubes containing a mysterious glowing blue liquid.

Tachyon's full racing outfit also features a yellow sweater vest worn over a black collared shirt with a blackish-dark-navy necktie, in a style similar to that favored by some real-life scientists. This outfit also has black pantyhose and white, 'high, heeled-boots'