Comic-Con: 'Arrow' Debuts Season 5 Trailer, Sets Katie Cassidy's Return

Arrow just revealed the resolution to one of its biggest cliffhangers of season four.

During the show's San Diego Comic-Con panel on Saturday, executive producers Marc Guggenheim and Wendy Mericle debuted the season five trailer, and the footage finally revealed the promise Laurel (Katie Cassidy) made Oliver (Stephen Amell) agree to right before she died. 

"You're instinct has always been to go it alone," she told Oliver while laying in her hospital bed. "Ollie, you can't."

Her words are clearly the reason behind why Oliver recruits some new members for Team Arrow in season five, as revealed in the new trailer. In the absence of Diggle (David Ramsey), Thea (Willa Holland) and Laurel, Oliver and Felicity (Emily Bett Rickards) attempt to train amateur vigilantes.

So who is the ominously dressed hooded figure who appears at the very end of the footage?

"Donald Trump," Guggenheim deadpanned. "No, he's a new character. He's our big bad for the year. We call him Prometheus. It's not the Grant Morrison-Howard Porter Prometheus from the Justice League. He's a new character that fits in with the theme of legacy for this season. He's pretty badass and mean."

And as viewers can see from the trailer, though Laurel was killed off last season, she will be back for the season five premiere. And Mericle revealed that Cassidy has signed a deal with all the DC TV shows — pacts similar to those of John Barrowman and Wentworth Miller — to appear in all three Greg Berlanti-verse shows, including The Flash and Legends of Tomorrow.

"She's definitely not gone," Mericle said to cheers from the Ballroom 20 crowd.

Guggenheim then revealed that the upcoming 100th episode will be episode eight this season — and a key episode for the upcoming four-show super crossover. 

"Turns out 508 is chapter two of our four-part crossover," he said. "And then 509 is our midseason finale. It's actually timed perfectly."

The panel then ended with Amell, Rickards, Barrowman and new series regular Echo Kellum serenading the audience with a pleasant rendition of "You'll Be Back" from Hamilton, with the rest of the cast and the crowd joining in at the end. 

Arrow returns for season five on Wednesday, Oct. 5, at 8 p.m. ET/PT on The CW.

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