Anime relies on a wide variety of tropes, clichés, and conventions to tell a story. Some are idiosyncratic, such as shouting attack names or comedic chibi forms, but others are more common among all types of fiction, such as characters with amnesia. This particular trope is popular in a variety of media. Lost memories can be a fascinating plot device if used correctly.
Source：https://www.cbr.com/anime-characters-lost-memories-amnesia-natsu-light-casca/
