Yoshimo is a trainee recruited to fight the Heirs of Kemmler and to stop the Darkhallow from being performed on Halloween. She was recruited because of sudden serious shortage of wardens due to The War.
Yoshimo's magic specialty is wind control.
In the series
In "War Cry", Yuki's leg has healed, allowing her to lead her fellow Wardens in a run to Montezuma. There, she joins in the defense of a group of Venatori guarding a shoggoth and is captured with Carlos Ramirez by Baron Bravosa.
In Peace Talks, she is part of the Council's delegation to the gathering of accorded nations. Before the event, she and the other Wardens confront Dresden about his connections with the White Court, and she performs a divination spell on him to ascertain whether he has had sexual relations in the last few hours. During the opening of the talks, a Sidhe musician who is attracted to her tries to mind-control her, but it does not work for long, and the event causes a minor disturbance in the evening.
In Battle Ground, she takes part in the defense of Chicago from the Fomor and the Last Titan. Yoshimo is part of a group including Harry Dresden, Wild Bill, Carlos Ramirez, Chandler, and River Shoulders that engages a group of Black Court vampires led by Drakul to perform necromancy in Graceland Cemetery. After a short fight, Yoshimo is murdered by the vampires, who escape with her corpse.