The 100 season 5 appears to have completed its main Eligius trio, as William Miller joins Ivana Milicevic and Jordan Bolger.

TV Line once again has the exclusive casting news for The 100 season 5, revealing that Spanish actor William Miller will play the villainous Robert McCreary.

Robert is arriving aboard the Eligius prison transport ship which set out from Earth over 100 years ago, and which has been keeping its inhabitants locked in cryo ship for the majority of that time.

Related: The 100 season 5 adds Ivana Milicevic as a ruthless recurring guest star

This means that he is one of the few characters on The 100 who will remember the world as it was pre-apocalypse, and his past will be jarringly familiar to us. He is described as a “mysterious prisoner aboard the long-distance mining mission sent from our time. A former enforcer from a powerful crime syndicate, his ruthless, violent methods make him a formidable antagonist to our heroes.”

William Miller is no stranger to showrunner Jason Rothenberg, having starred in the ill-fated Searchers pilot. While The CW ultimately did not pick up Rothenberg’s new series, Miller was brought back to the mothership, with Rothenberg telling TV Line that they “fell in love with William [on Searchers] and are thrilled to be working with him again on The 100.”

Miller is the third announced cast member to join The 100 season 5 in a recurring role. At San Diego Comic-Con 2017, Rothenberg revealed that we could expect three “powerful” new characters to join the fray, which may or may not be Robert, Charmaine Diyoza (Milicevic) and Zeke Shaw (Bolger).

Rothenberg said the Eligius prisoners will “seem like villains,” and will “ultimately be a threat” to our heroes, but “we’re gonna find some guys in there that we really like.”

While there are “no good guys” on The 100, the series doesn’t shy away from portraying certain characters as less good than others, and it sounds like Robert — an actual criminal from our time — might fall into the villain-ish category, becoming the ‘big bad’ of the season.

Or he could reveal himself to have hidden depths, becoming an unlikely ally to (some of) the characters we know. Eligius, after all, theoretically has as much of a claim to the small part of Earth that is inhabitable as any of the other factions of characters, and we will presumably be encouraged to sympathize with them in order to further muddy the waters of morality, as The 100 is wont to do.

It is also worth noting that, so far, all the introduced Eligius characters are played by European-born actors (Miller is of American and British parentage but has lived most of his life in Spain; Bolger is British, and Milicevic is Croatian, born in Bosnia), though we don’t yet know if this has any impact on their in-show nationalities.

The 100 season 5 has also promoted Tasya Teles (Echo) to a series regular, and has re-cast the role of Madi with Shadowhunters actress Lola Flanery.

The 100 season 5 premieres in early 2018 on The CW. The previous four seasons are available on Netflix now!