Ichiyon personifies the Springfield Armory-produced American M14 battle rifle. As the elder sister-in-law from the Springfield family to Ichiroku (the Colt family-adopted M16A4), she shares a foster sibling bond rooted in their rifles' shared design heritage. She rooms with Fal (L1A1 battle rifle).

A noticeable beauty emerges only when Ichiyon stays quiet, as her typical demeanor is crude, rowdy, and tomboyish. She is boisterously loud, constantly annoying others—especially Ichiroku—with incredibly lame puns she delivers huskily and perceives as smooth.

Ichiyon participates in significant combat, such as the Seishou Academy versus Red Steel High conflict at Hakone, where she delivers suppressive fire. She holds a rivalry with AK-pattern firearms, stemming from Cold War-era design competitions.

Beneath her rough exterior, Ichiyon displays vulnerability and camaraderie. She clings to Jeethree (G3A3 battle rifle) in a "Nyandere" style, pleading to learn her secret technique; these training sessions evoke slight embarrassment in her. She also engages in teasing behavior, like singing "You can do whatever you want with me" provocatively to Elle (L85A1) during a bath scene. Her role remains that of a supporting character defined by these relationships and interactions within the school setting.