There is no formula that can explain Supernatural‘s success. If there were a way to pinpoint exactly how the show has become the longest-running fantasy/sci-fi show in the U.S. with one of the most passionate fanbases in all of television, well, every show would be copying it. But even Supernatural has struggled to re-create its magic in the form of a spin-off.

Back in season 9, Supernatural aired its first backdoor pilot for a potential spin-off that would be called Supernatural: Bloodlines, a show that would follow mobster monster families in Chicago. The characters were new, the idea was new, and without Sam or Dean (or really much Supernatural), it didn’t catch on. In other words, attempt one was just a bit too far from the world fans had come to love, and it was a mistake the writers wouldn’t make again.

After years of laying groundwork, Supernatural aired the backdoor pilot for Wayward Sisters on Thursday. Wayward was an idea that was born when Alex Jones went to live with Jody Mills in season 9, followed by Claire Novak doing the same in season 10. It was an idea that the fandom latched onto — creating campaigns and spreading their own idea for the Wayward Daughters Academy — but despite the obvious passion from the viewers, the writers took their time. In the following seasons, we continued to check in with Jody and Claire and Alex and Donna until, in season 13, the show introduced two new faces: Patience and Kaia. Only then did the writers deliver a backdoor pilot that was worth the wait.

Wayward Sisters, which followed all six women as they came together to save Sam and Dean, worked for a number of reasons. It worked because it felt like Supernatural. And it worked because it didn’t. Unlike Bloodlines, Wayward has a very strong connection to Supernatural, and it was able to embrace where it comes from without having that define it, even having dialogue that mirrored the Supernatural pilot. It said, “Yes, this is a similar story to Supernatural, but it’s not the same story.” Wayward took the things that worked for Supernatural — family, tragedy, badassery — and made them work for it, too. But it also made sure to establish itself as its own entity.

By focusing on six women, Wayward was already going to be different from Supernatural, but the key factor was always going to be the chemistry between these characters. What would Kaia bring out in Claire? What would Alex bring out in Patience? Sure, we’d met all the women before, but it was what they did as a group that really made the show work. It was Patience’s shock at this absurd lifestyle. It was Jody’s heart, Claire’s drive, Alex’s dependability, Kaia’s bravery, and Donna’s humor. It was all of it together.

And it was the fact that Wayward took risks. Spoiler alert if you haven’t watched the hour, but not everyone gets out alive. By killing one of the characters fans were just falling in love with, it made a statement. And regardless of what the hour’s final twist — yes, there was a twist! — means for the character and the show, they made it known that this is a dangerous business and people die. (Plus, that twist ended the pilot with the kind of excitement and momentum you want going into any new series.)