Early Monday, Marvel dropped the highly anticipated trailer for Deadpool & Wolverine, in which Ryan Reynolds and Hugh Jackman reprise their roles after leading their own movies, Deadpool and Logan. Deadpool & Wolverine officially marks Deadpool’s . But Deadpool isn’t the only one making an MCU debut. As the trailer reveals, villain Cassandra Nova, played by ’s Emma Corrin, is being introduced into the ever-expanding universe.

Who is Cassandra Nova and how does she fit into the MCU?

Cassandra Nova will be facing Deadpool and Wolverine as the pair try to work together to save the universe in the new movie, out July 26. The first Marvel release of the year, coming after the studio from three movies a year to one, sees Deadpool being recruited by Paradox (played by Matthew MacFadyen), an agent at the Time Variance Alliance, for a mission that will change “the cinematic universe forever,” Deadpool says in the recently released trailer, and set up the future of the Avengers movies.

In the trailer, we see a Wolverine variant, wearing the classic blue and gold suit (the first time Jackman’s character has worn the suit in a live-action movie), that “let down his entire world.” Deadpool enlists Wolverine’s help to save his own world to ensure the safety of his newfound friends and family. The two seem to be going to “Battleworld,” which, , is made up of the “remnants of destroyed realities following the Multiverse’s collapse.”

As the trailer shows, the pair faces obstacles, including a bald woman with telekinetic powers fighting against Wolverine. This is ’s twin sister, Cassandra Nova. According to the Marvel comics, while in the womb together, Charles “recognized her evil presence and killed” Cassandra, resulting in her stillbirth. Over the years, she formed a new body, intent on getting revenge on Charles.

It’s unclear what Cassandra’s motives are in Deadpool & Wolverine. The trailer gives us a glimpse of what’s to come. About halfway through it, she appears and says, “Boys are so silly.” Time will tell what to expect from this new character, but she seems to be one to watch out for.