This is where a character from a previous work is appropriated for a newer, relatively unrelated one as a regular. This isn't an Expy or Captain Ersatz, this is the original character with all their backstory. This is different from a Crossover where several characters from two or more works join up for a single event or for an entire Serial, though an Imported Character resulting from a Crossover does count; a Spin Off would technically count but in these cases the works are explicitally linked from the start. In non-official filmed works The Other Darrin will often be used, and The Nth Doctor is another possibility. Bearing this in mind, some changes to the character are allowed to be changed so long as in name and basic personality/backstory they are still the same. The Trope Codifiers are the That Guy With The Glasses versions of Ma-Ti (Captain Planet), Terl/Turrell (Battlefield Earth) and Genral Zod (Superman), as portrayed by Bhargav Dronamraju, Noah Antwiler and Doug Walker respectively; first appearing in The Nostalgia Critic reviews of their original work in the case of the first two, and in the Merry Zodmas special in Zod's case.
Hello, Unkown Troper. You'll need to get known to lend a hand here.
Three days must pass before this YKTTW is Launchworthy or Discardable