"Crisis on Earth-X": Who Is Citizen Cold?

The much-anticipated "Crisis on Earth-X" continues tonight, and while there are plenty of familiar faces populating both the Earth we know and the dark, brutal Earth-X, there is a specific face sure to make Arrowverse fans very happy: Wentworth Miller as Leonard Snart.

Spoilers for hour two of the Arrowverse crossover event, "Crisis on Earth-X", below.

However, this Leonard Snart isn't the villain turned anti-hero we saw sacrificing himself for the team on Legends. This Snart is Citizen Cold, hero from the Nazi-ruled Earth-X, and while he has Captain Cold's same wisecracking demeanor, Citizen Cold has a very different ideology and approach to heroism.

DC Comics fans may already be familiar with Citizen Cold, but for those who aren't, here is a brief primer. In comics, Citizen Cold is a hero from the Flashpoint timeline where he, not the Flash, was Central City's main hero who, while fighting on the side of justice, doesn't hesitate to kill if need be. He also has no problem killing to keep his own secrets -- including his past as a low-level criminal.

Earth-X's Citizen Cold appears to be a departure even from the comics character. As we see he does kill as necessary -- specifically Nazi guards when he's breaking the Arrowverse heroes and Earth-X's The Ray out of the concentration camp right before being executed -- but has some marked differences. On Earth-X, Citizen Cold isn't exactly Central City's primary hero and is part of a team, and it's not one that he's in charge of.

Citizen Cold also marks Miller's return to the Arrowverse. Miller's part in the crossover was revealed earlier this month, and it's also not going to be the last time that we see Miller as some version of Leonard Snart, at least not yet. Wentworth is set to reprise his role as Captain Cold in upcoming episodes of Legends of Tomorrow, though Miller also announced previously that it will be his final turn as the fan favorite. Miller said he would be ending his time in the Arrowverse this season.

"Crisis on Earth-X" concludes tonight with episodes of The CW's The Flash and Legends of Tomorrow beginning at 8/7c.