Border Enlistment Arc
Yuba is mentioned as one of the 8 candidates for Fūjin by Yūichi Jin.
B-Rank Rank Battles Arc
Through Kazuma Satomi, who talks enthusiastically about Yuba's combat prowess to Osamu Mikumo,[1] Shun Midorikawa arranges for Yuba and Yūma Kuga to meet.[2] Yuba has Yukari Obishima introduce herself to Kuga, whom she admires, and when he mistakes her for a boy, Yuba forces him to spar with her as an apology. When Yūma stops holding back and shows off a new technique, Yuba has a round against him and defeats him in an instant with his quick draw.[3]