Karlamine

Riser's Knight dressed in armor and armed with a sword and dagger. Karlamine is a expert swordswoman and is capable of using fire and wind-based attacks and is known as the Knight of Flames (炎の騎士 Honō no Kishi). According to Ravel, she is a sword maniac like Yuto with a similar sense of honor, as she was unhappy that her fellow pieces were used as sacrificial pieces but endures it as it was at Riser's command. She was able to fight on par with Yuto before Issei gains a new ability in the form of the Boosted Gear Gift, where she is defeated by their combination attack.

(Source: Wikipedia)