Translation guide
A character in a story, film, game, etc. who is not a main focus; often appears in the background or has a minor role.
A character with a small role, not central to the plot.
Literally 'side role'. The most common term for a supporting or minor character in a story, play, or film.
彼はいつも脇役ばかり演じている。
He always plays minor roles.
A very small or bit part, often with few lines. More specific than 脇役.
その俳優は端役で映画に出演した。
The actor appeared in the movie in a bit part.
From 'mob character'. Used in anime/manga/game contexts for background characters with no individual identity.
このゲームのモブキャラはみんな同じ顔だ。
The background characters in this game all have the same face.
A person appearing in the background of a scene, often without lines.
Borrowed from English 'extra'. Standard term for a background actor in film or TV.
彼女はエキストラとして撮影に参加した。
She participated in the filming as an extra.
Literally 'background person'. A straightforward, casual way to refer to someone in the background.
あの背景の人はずっと立っているだけだ。
That background person is just standing there the whole time.
A character so minor they are not given a name or development.
Literally 'nameless character'. Used when a character has no name or is treated as insignificant.
名無しのキャラが突然殺された。
A nameless character was suddenly killed.
Means 'the rest of the many' or 'the crowd'. Refers to a group of unimportant characters collectively.
主人公以外はその他大勢だ。
Everyone besides the main character is just part of the crowd.
脇役 is a supporting role that may still have some importance, while 端役 is a very minor role with little to no impact on the story.
Avoid directly translating 'background character' as 背景のキャラクター. While understandable, it sounds unnatural. Use the terms above instead.