Arrow type TV Show network The CW genre Superhero

Warning: This post contains spoilers from Monday’s Arrow episode, “Elseworlds, Part 2.” Read at your own risk!

Supergirl (Melissa Benoist) and Batwoman (Ruby Rose) took a big and unexpected step toward friendship in the second part of “Elseworlds.”

In tonight’s episode of Arrow, Oliver (Stephen Amell), Barry (Grant Gustin), and Kara finally met Batwoman when they traveled to Gotham City to find Dr. John Deegan (Jeremy Davies), who was responsible for rewriting reality. Although Kate Kane wasn’t too happy to have these other capes in her city, she helped them in multiple ways, from giving them a place lie low while they regrouped to helping them out when they got caught in a prison break at Arkham City.

But the best thing about Batwoman’s introduction was her burgeoning friendship with Kara, which EW teased before the episode. While the trinity hung out in a rundown Wayne Enterprises building, Kara and Kae formed a connection, and when their Gotham adventure came to an end, Kara revealed to Kate that she used to her X-ray vision to find out she was Batwoman. Now Kara knows Kate’s secret idenity, and Kate knows Kara. Superhero shows tend to hold the secret-identity card for as long as possible, but Batwoman executive producer Caroline Dries felt it was an important moment to include in the crossover.

“It was important for us, I think, to sort of humanize Kate that made her relatable to the other characters in the Arrowverse,” Dries told reporters at a screening of the crossover. “Even though we’re creating this sort of enigmatic character, we wanted sort of an in to her, and in our minds, Kara, obviously, has this cousin, [and] she’s sort of in his shadow and her story was getting out of his shadow, and that’s exactly Kate’s story. So it was just important for us to kind of find a moment for them to bond, and I thought, ‘Well, Kara has X-ray vision, you know, she can figure these things out pretty quickly,’ so it just felt like the right moment, the right move.”

During the aforementioned prison break, Barry and Oliver got doused with Scarecrow toxin and started hallucinating that they were fighting each other’s archenemies — Barry saw Malcolm Merlyn (John Barrowman), and Oliver saw Reverse Flash (Tom Cavanagh) — when in reality they were fighting each other, in another great callback to the first crossover.

“I think that was always kind of the conceit because it’s their origin story, it’s their season 1 big bad, and it’s kind of made both characters who they are,” said Arrow showrunner Beth Schwartz. “It allowed them to really understand one another from way back.”

Speaking of understanding each other, Oliver and Felicity (Emily Bett Rickards) were able to work through their marital issues by the end of the episode too. The last time we checked in with Olicity, they’d reached an impasse because Oliver wasn’t okay with how much Felicity had changed while he was away; however, the body swap helped Oliver understand that no matter how much they change, their love will remain the same. But will this resolution last beyond the crossover?

“Yes, they’re made up. They’re in a good place now,” confirmed Schwartz, before explaining how she had to fit Oliver and Felicity’s relationship story into the crossover madness. “Since [Arrow consulting producer Marc Guggenheim] wrote [episode 9] and I wrote [episode 8] and knew what the arc was, we just kind of worked together to make sure that it all came together as a piece,” said Schwartz. ” I think it worked out kind of perfectly because as, well, she’ll say, I guess not until the episode after that, but just the fact that he became a different person literally in the crossover and she’s become a different person, he was able to understand her journey, which made for a perfect time to realize that he might have been overreacting in episode 8, and it was a nice resolution as well.”

Image zoom Jack Rowand/The CW

Finally, the second hour of the crossover also featured John Wesley Shipp as Barry Allen from Earth-90, a.k.a. ’90s Flash. After the Monitor destroyed his Earth, he traveled to Earth-1 that the Monitor is essentially using the Book of Destiny to test realities in order to see what can withstand forthcoming a threat, or a crisis, if you will. (The shot of ’90s Flash coming through a breach was a reference to Crisis on Infinite Earths.) While none of the producers can remember who came up with the idea to include ’90s Flash in the crossover, it’s still one of their favorite moments of the crossover.

“I do remember when it came up in the room, and I just got chills,” Supergirl co-showrunner Robert Rovner told reporters. “The idea that our universe was part of all the universes was kind of an amazing idea.”

Added Schwartz, “Geoff Johns was in the room with us, and I just remember him being like, ‘’90s Flash!’ He was so excited.”

“Elseworlds” concludes with Supergirl tomorrow night at 8 p.m. on the CW.