Bertille Althusser

A high school senior at Winfield Academy where she's a top level jouster. Coming from an incredibly rich family who owns several mansions near the academy, she serves as a "rich bitch" semi-antagonist to the main character Sakura but warms up to her by the middle of the series. Proud of her noble lineage and especially her huge bust, she paradoxically doesn't like to be seen in a one-piece swimsuit but also is willing to joust without any pants on just wearing a lace thong.