“DC’s Legends of Tomorrow” and “The 100” already share a network, a night and a plot that involves a bleak post-apocalyptic future, but this week the two CW shows will have something else in common, when “The 100” alum Cory Grüter-Andrew (who played Lexa’s favored Nightblood Aden this season, before meeting a grisly demise at the hands of rival warrior Ontari) guest stars on the time-traveling superhero show.

In Episode 10 of Season 1, titled “Progeny,” Rip (Arthur Darvill) tells the team they are headed to the future to take out a powerful ally that Vandal Savage (guest star Casper Crump) needs in order to conquer the world. However, when Rip reveals the ally is a 14 year-old boy (Gruter-Andrew) who will one day grow into an evil dictator, the team is split about the morality of killing a child, even if it does save the world.

As seen in Variety‘s exclusive preview clip from the episode, Grüter-Andrew is playing DC Comics villain Per Degaton, who has the ability to travel through time in DC Comics canon, and as far as Rip is concerned, the boy’s instrumental role in Savage’s ultimate plan makes him collateral damage in their war with the villain.

Elsewhere in the episode, Sara (Caity Lotz) talks Snart (Wentworth Miller) through a rough patch and Ray (Brandon Routh) learns something that could impact his future with Kendra (Ciara Renée).

“DC’s Legends of Tomorrow” airs Thursdays at 8 p.m., and “The 100” airs Thursdays at 9 p.m. on The CW.