Mr. Miyagi

Nariyoshi Keisuke Miyagi, also known as Mr. Miyagi, is a fictional character played by Pat Morita. Mr. Miyagi is the karate teacher from the movies The Karate Kid, The Karate Kid Part II, The Karate Kid Part III and The Next Karate Kid. He’s also in flashbacks in the television show Cobra Kai.
Backstory.
Mr. Miyagi was born in Okinawa and was taught karate by his father a fisherman and used it to stop people from killing him. Mr. Miyagi fell in love with a woman named Yukie who had an arranged marriage to Miyagi’s friend Sato so Sato asked for a fight to the death. Instead of fighting Sato, Mr. Miyagi left Japan and went to the United States of America and married a Japanese American woman. Mr. Miyagi fought against the Japanese Empire in the Second World War and while he was doing that his wife Mrs. Miyagi, gave birth to a son inside an internment camp and got sick and they didn’t send any doctor to her so she and the son both died. Mr. Miyagi still won a medal of honour for being a war hero.
Role in The Karate Kid.
In the movie The Karate Kid, Mr. Miyagi teaches Daniel LaRusso karate and teaches him that the reason to learn martial arts isn’t so that he will be good at fighting but so that he won’t have to fight.
Role in the Karate Kid 2.
In The Karate Kid Part II, Mr. Miyagi goes back to Okinawa after he finds out his father is dying and brings Daniel LaRusso with him. Mr. Miyagi’s father dies and Mr. Miyagi’s old friend Sato still wants to kill him but after Mr. Miyagi saves him from a hurricane, Sato gives up on revenge. Mr. Miyagi also warns Daniel LaRusso before Daniel fights Chozen to the death that “this not tournament, this real.” 
Role in the Karate Kid 3.
In The Karate Kid Part III, Daniel wants to fight in the karate tournament to get money but Mr. Miyagi tells him not to do that because he doesn’t believe in fighting for glory. So Daniel asks Terry Silver to train him and keeps that a secret from Mr. Miyagi. Then Daniel realizes that he’s broken Miyagi’s rules about only fighting for defence and never revenge and apologizes to Mr. Miyagi and Mr. Miyagi forgives him and saves him from John Kreese. 
The Next Karate Kid.
In the movie, The Next Karate Kid, it turns out that in the Second World War, Mr. Miyagi’s friend Jack Pierce saved his life so Mr. Miyagi thanked him by teaching him karate. Jack Pierce taught that karate to his son and Pierce’s son taught karate to his daughter Julie Pierce. Then Julie’s father and mother died in a car accident so Julie’s grandfather Jack Pierce decided to teach her karate and then died of old age. Mr. Miyagi later teaches Julie karate so she can feel closer to her dead parents and grandfather. And at the end of the movie, Mr. Miyagi fights Colonel Dugan, the main villain and wins. 
Mr. Han.
In the 2010 reboot of The Karate Kid, Jackie Chan plays a character called Mr. Han who is based on Mr. Miyagi but teaches kung fu instead of karate.
Cobra Kai.
Many of the characters in Cobra Kai talk about Mr. Miyagi but because of Pat Morita’s death he only ever appears in flashbacks using archival footage.