Swords and Rings Episode 5

The Bubuki battle continues aboard the train that's carrying Oubu toward Treasure Island. A beam fired from Arabashiri's Bubuki ring hits Kinoa, causing her own past to replay in her mind and slow her down. Azuma tries to help, but Kinoa stops him, saying she must settle her own score with Arabashiri. So Azuma agrees to just watch, but Hiiragi can't help wondering what Kinoa's relationship with Arabashiri is. What really happened in their past?