Characterization

Characterisation or Characterization (depending on your country of origin), is how a character is described; the traits, actions, manner of speaking etc that make them them. It isn't enough to just weld a name onto an amorphous humanoid thing and make it do what you like; if it doesn't speak like the character, act like the character or do the things the character would do, then it probably isn't the character. When this happens, the real character has been sucked into a Plothole, and their place usurped by a Character replacement. Agents must in these cases kill the replacement and find the real character.