Ensemble Darkhorse/Sandbox

">gets one﻿ minute of screentime

>has the biggest fanbase"

- YouTube comment by lern2surture, on Princess Luna from MLP:FIM

The term "Dark Horse" has its origin in horse racing. A relatively unknown horse would be risky to place bets on, compared to a horse with a known track record, because the gamblers would be "in the dark," so when an unknown horse won a race it was called a "Dark Horse Victory." The term is also used in politics to describe a lesser known candidate who does better than expected in an election.

Generally, it's used to describe a side character making up part of the Ensemble, either a non-lead secondary character or a mere Flat Character, who can sometimes become unexpectedly popular with the fandom (sometimes, even more than the lead characters) depending on who and where the Fandom is, as well as what the other characters are like in comparison (for example, the hero is not as popular because s/he is too much The Everyman).

The writers or producers may be tempted to Retool the show's premise to put them in the spotlight. Sometimes this works, but usually it's a bad idea for two reasons, both relating to what happens when you take a supporting character and move him or her into the protagonist's position. The first is that writers often "adjust" the character so that s/he can fit into a conventionally heroic role -- in the process destroying the unconventional traits that made the character an Ensemble Darkhorse in the first place. The second is that if the writers don't do this, traits that were entertaining in a secondary character may become grating and unpleasant in The Protagonist.

However, it's still good business to bring Darkhorse characters back, even if they were originally meant to be featured for only a short time. Thus, episodes which do not specifically require a certain character will be more likely to use the Ensemble Darkhorse.

Occasionally, if an antagonist becomes a Darkhorse, the writer may decide to have him perform a Heel Face Turn in situations where the only other option is being killed by the protagonists. However, if the series doesn't have an end planned, it's more likely that he'll just escape.

See also Breakout Character, Adaptational Badass, Ascended Extra, Memetic Bystander, Lower Deck Episode, A Day in the Limelight, and One-Scene Wonder. Creator's Pet is the polar opposite, a character who becomes prominent despite the fans' wishes. A character who becomes popular despite the author's intentions is Draco in Leather Pants -- an example of Misaimed Fandom. The natural extension of this is the Spotlight-Stealing Squad.