Marvel Studios recently dropped the trailer for Avengers: Infinity War — the biggest silver screen coming together of superheroes from the Marvel Comics canon. But it is also the beginning of the end, sort of.

The cinematic universe made a big-bang box-office entry with Iron Man (2008) and changed the live-action film genre forever. Infinity War and the yet-untitled Avengers 4 will signal the end of Marvel’s “Phase Three” films and, with it, certain characters as well.

Marvel boss Kevin Feige told Collider: “Our focus is on the next six movies. Finishing the first three phases, getting Untitled Avengers out into the world in May ’19 before publicly focusing on anything else.”

That said, the end could come sooner. Not the end of the cinematic universe, per se, but a lot of characters the audiences have grown fond of. Several actors are on the final leg of their contracts, and Infinity War and Avengers 4 could provide a springboard for potential goodbyes and welcomes. The studio’s huge catalogue of characters will also make its search for the next big screen star easier.

Marvel has been building up to this eventuality of phasing out some big guns and introducing new characters such as Ant-Man, Doctor Strange, Black Panther, and Star-Lord and Drax in Guardians of the Galaxy for some time. These additions would allow the studio the opportunity to explore newer directions and storylines.

“Finale” has been loosely used to sum up the conclusion of the universe at the end of Avengers 4. But the “finale” will only bring the curtains down on one storyline, considering Thanos has lurked in the background for 10 years. Each subsequent film since Iron Man was bigger, and with almost every character appearing in Infinity War and Avengers 4, this storyline will bow out in style.

Speaking of the success of the Marvel Cinematic Universe, and the failure of Marvel Comics canon at the hands of other studios, Feige told Vanity Fair: “In my seven years, from 2000 to 2007, before we started Marvel Studios, you can see movies that worked and the movies that didn’t work.”

Feige and Avi Arad, original head of the studio, said while the film deals for Fantastic Four, X-Men and Spider-Man that Marvel Comics had with other studios didn’t help, they took it as an opportunity to explore lesser-known characters. “We didn’t have Spider-Man. We didn’t have Fantastic Four. I knew that Iron Man was really cool and Hulk was, arguably, next to Spider-Man... I thought they all had amazing potential, but the goal was deliver these two movies, and make the best Iron Man film we could, and make the best version of Hulk,” Feige said.

And that risk has kept the cash register ringing enough for it to make plans for 20 more films after Avengers 4.