Tougijou no Reijou Erina

Erina, an arrogant and prideful countess. Despite her skills, which once earned her the title of knight commander— She’s falsely accused of a crime, exiled from her homeland, and reduced to slavery. The one who buys her is none other than her former subordinate. Now a slave, Erina clings to the pride of her noble upbringing. Until she repays the price paid for her, her days as a slave will continue. To escape her bondage as quickly as possible, she decides to become a female gladiator, earning prize money by fighting in the arena. What harsh fate awaits the former countess, Erina?! [Translated from dlsite]