Mr. Miyagi is an essential character within The Karate Kid universe, and his heartbreaking military backstory helped inform his mentor-like relationship with his protégé, Daniel LaRusso. First introduced in the original The Karate Kid in 1984, Mr. Miyagi was expertly portrayed by Pat Morita in the original series and has continued to appear in archival footage in the sequel television show Cobra Kai. While Mr. Miyagi’s calm demeanor and defense-based martial arts wisdom have always guided Miyagi-Do students toward noble victory, his character’s stoic nature and deep philosophical wisdom were born from a traumatic backstory of loss, pain, and war.

https://screenrant.com/the-karate-kid-mr-miyagi-tragic-military-backstory/