I got a question for you: Kan'ami Kiyotsugu and his son Zeami Motokiyo brought Noh to what is essentially its present-day form during the Muromachi period (1336 to 1573). Kan'ami was a renowned actor with great versatility fulfilling roles from graceful women and 12-year-old boys to strong adult males. When Kan'ami first presented his work to 17-year-old Ashikaga Yoshimitsu, Zeami was a child actor in his play, around age 12. Yoshimitsu fell in love with Zeami and his position of favor at court caused Noh to be performed frequently for Yoshimitsu thereafter.

Answer this question: the most important figure in the history of japanese nō theatre is?
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Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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To answer the above question, the relevant sentence is: Kan'ami Kiyotsugu and his son Zeami Motokiyo brought Noh to what is essentially its present-day form during the Muromachi period (1336 to 1573).
Therefore, the answer is Kan'ami Kiyotsugu.