Eien no Zero 

Kentaro, 26 years, is a NEET. At the request of his sister Keiko, the young man plunges into his family past. Kyuzo Miyabe, his grandfather, was a fighter pilot of the Japanese imperial navy who had fought at the commands of the mythical Japanese fighter aircraftt: "Zero". But at the end of the war he die in kamikaze attack. Was he the hero whom everybody claims? Or rather a terrorist? A coward?