There is a theory that 'Ura' was actually toraijin (immigrants, mainly from China and Korea), who had been giving steel manufacturing techniques to the former rulers of Kibi Province, or local ruling families, and out of loyalty to the former rulers, they fought against Kibitsuhiko (or Yamato rule).
実際には「温羅」とはそれまで吉備国を支配していた旧勢力に製鉄技術を供与していた渡来人もしくは地来の豪族であり、旧勢力に義理立てするために吉備津彦（ひいてはヤマト王権）と戦ったと言う見方がある。