Oshiro first appears in the beginning of Obsidio, where she talks back to Lieutenant Christie and is tasked with showing new ground pounder Rhys Lindstrom the ropes as punishment.
She gradually takes a liking to Rhys, inviting him to play secret games of cards with the other ground pounders and helping him out when he gets caught in various scrapes, like when he is caught in a restricted area with Asha Grant.
In the aftermath of the fight between BeiTech and the Kerenza rebellion, Katya Kowalski is accidentally shot. Upon hearing Asha’s unintentional repeating of her father Masuro Oshiro's words ("A soldier's first duty is to his conscience") as she begs them to help, Oshiro orders her medics (Carson and Shah) to assist Katya.
Sergeant Oshiro comes off as harsh and uncaring from her time in the BeiTech forces, but when she is given the option to follow in her father's footsteps and follow her moral compass, she does. She is unexpectedly kind at times, stepping in and using her authority as leverage to help people.
Oshiro is described as having black hair cut in a bob and hard brown eyes. She is only a little older than her fellow ground pounder Rhys but a foot shorter than he is, looking to be of Japanese descent and partly Eurobloc.
- Oshiro has a fifteen-centimeter scar below her collarbone, inflicted by a person named Aisling Wood.