original_query: Who were the descendants of Oi, the sixth son of Watanabe Hisashi, that were killed in battle against the Mongols?
query: Who were the descendants of Oi, the sixth son of Watanabe Hisashi, that were killed in battle against the Mongols?
answer: Sashibo, the heir of the Matsuura Watanabe, and his cousin Yamashiro Kai, from the Yamashiro Watanabe branch, were killed fighting against the Mongols.