German actress Nadia Hilker has been tapped to portray a mystery role in The CW's "The 100" season 3, but is she going to be a threat to Clarke (Eliza Taylor) and the group?

Hilker, known for her appearance as Nita in the film adaptation of "Allegiant," is reportedly joining the cast of the post-apocalyptic dystopian drama for at least two episodes. Since "The 100" season 3 is down to its last three episodes, it could mean that Hilker's mysterious character will appear in the two-part finale of the season.

The Wrap speculated that Hilker could possibly portray the role of Luna, a character that has been mentioned by Lincoln (Ricky Whittle) since season 1 but remains faceless if not for the Grounder's drawing in his journal.

However, Hilker's character could also be introduced in the upcoming episode, called "Join or Die," as TVLine revealed that a new group of Grounders will emerge from an unexpected location. This could mean that the new character could be a part of that group.

Meanwhile, the past and current chancellors of the Arkadia, Kane (Henry Ian Cusick) and Pike (Michael Beach) will have an ugly encounter with the other former chancellor, Jaha (Isaiah Washington), as the two become the newest captive of the City of Light.

In the sneak peek for the upcoming episode, Kane and Pike are forced to enter Jaha's new congregation, where they are shocked to see a dead man hanging. Jackson (Sachin Sahel) emerges to greet them, much to Kane's surprise. Then Jaha appears with a Grounder commander, who makes a Grounder warrior swallow the City of Light pill.

Pike attacks the commander and warns everyone that if they attempt to come near him he will kill her. When he sees two of his former soldiers, Pike orders them to get behind him. But he did not expect to see his former troops arrest him, as they all sided with Jaha and the City of Light. Could Pike and Kane still escape Jaha and his plans to make everyone swallow the City of Light pill?

The official synopsis for the upcoming episode reads:

"Clarke is on a mission that could change everything. Meanwhile, Murphy (Richard Harmon) gains insight that might prove useful in ensuring his survival. Lastly, Kane reaches a breaking point."

"The 100" season 3 episode 13 airs Thursday, April 28, on The CW.