As John Constantine helps the Legends of Tomorrow travel through time and space to confront all sorts of occult and mystical threats to the space-time continuum, the paranormal hero may end up having to deal with a familiar face from his cancelled solo series as part of the Arrowverse. Longtime DC Comics villain Felix Faust had crossed paths with Constantine in a memorable appearance during the character's NBC series. With Constantine now firmly integrated into the Arrowverse, Faust could potentially return in some capacity, and he would immediately be a massive threat.

As Legends of Tomorrow nears the end of its fourth season and with the magical side of the DCTV Universe playing a more prominent role this season, here's everything you need to know about the character, his portrayal by Mark Margolis on Constantine, and how he could make his full Arrowverse return in the future.

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WHO IS FELIX FAUST?

Felix Faust was created by Gardner Fox and Mike Sekowsky in 1962's Justice League of America #10. As an evil sorcerer who has lived for millennia, Faust was trapped in an pocket dimension for centuries before accidentally being released in the 20th century. With his powers significantly reduced by his lengthy imprisonment, Faust targets the Justice League to manipulate the team into helping him summon a trio of ancient demons that can augment his magical abilities. However, he's thwarted by the assembled superheroes.

Over the years, Faust would constantly plot to boost his occult powers, usually by bargaining the souls of those around him to demonic forces, only to be defeated time and time again. After a grand scheme to fool the powerful demon Neron fails, Faust found himself as an unwilling vassal to the dark lord, putting him on a collision course with Ralph Dibney, Black Adam and Isis as he searched for ways to free himself from Neron's control.

FELIX FAUST ON CONSTANTINE

The Arrowverse version of Felix Faust had crossed paths with John Constantine some time before the events of the NBC series, where he was beaten at a game of poker by the younger magician. Initially dismissed by Constantine as a washed-up, past-his-prime conjurer who dabbled in black magic, Faust resurfaces much more dangerous than ever. Now commanding a much more powerful control over his magical abilities, Faust perfected a technique to steal souls from victims' bodies to boost his dark powers.

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After Chaz, Constantine's closest associate, had his daughter Geraldine's soul stolen by Faust, Constantine tracked down the older sorcerer to a warehouse just outside of Brooklyn. Holding Geraldine's soul hostage, Faust orders Constantine to banish a nearby demon back to Hell only for John to kill the demon instead when it nearly devours his ally Zed. Incensed, Faust refuses to return Geraldine's slow only for Chaz to trick him and blow the two up with a hidden grenade, freeing his daughter's soul along with all of Faust's other hostages.

IS FELIX FAUST PART OF THE ARROWVERSE?

Legends of Tomorrow John Constantine

Following Constantine's cancellation, Matt Ryan reprised the role on Arrow as an old ally of Oliver Queen's before the hero return to Starling City. Now firmly integrated into the Arrowverse, Constantine has teamed up regularly with the Legends of Tomorrow to help them eliminate supernatural threats to the space-time continuum. While only making passing, oblique references to his solo series, Constantine's past encounter with Felix Faust theoretically remains a part of the character's DC TV history.

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Given the supernatural nature of Faust and Legends of Tomorrow's central premise of traveling through time, a potential return for the villain could absolutely be possible. The DC Comics villain has overcome death before and he's arguably DC's greatest mystical villain, which could potentially position him as a major mystical player. Given the recent resurgence of paranormal threats, Faust would make a memorable returning antagonist that has a history with John Constantine. The Legends have faced magical opponents before and given the prominence of Neron in Season 4, the demon's comic book links could set the stage for a rematch between John Constantine and Felix Faust.

Airing Mondays at 8 pm ET/PT on The CW, DC’s Legends of Tomorrow stars Caity Lotz, Dominic Purcell, Brandon Routh, Nick Zano, Maisie Richardson-Sellers, Tala Ashe, Matt Ryan, Jes Macallan and Courtney Ford.