Welcome to The Hollywood Reporter's weekly DC TV Watch, a rundown of all things DC Comics on TV. Every Friday, we round up the major twists, epic fights, new mysteries and anything else that goes down on The CW's Arrow, The Flash, Legends of Tomorrow and Supergirl and Fox's Gotham. While all the DC TV shows are on summer hiatus, THR breaks down all the latest news heading into their returns in the fall.

Crossover revealed | Before getting into your regularly scheduled DC TV Watch programming, it's time for a crossover announcement: The CW has officially set the next four-show crossover for the Arrow-verse. Switching things up this year, the crossover will now take place over two nights instead of four, beginning on Monday, Nov. 27, with an episode of Supergirl leading into an episode of Arrow (which will move to Monday night one time for this special event). It will conclude on Tuesday, Nov. 28, with an episode of The Flash leading into Legends of Tomorrow. But that doesn't mean there will be a double dose of Arrow that week (which, come fall, airs Thursdays). "We haven't figured out how we're going to schedule, but no, the crossover is going to be it for that week's airing," CW president Mark Pedowitz told reporters at his stop at the Television Critics Association's summer press tour this week. "I don't know whether we're going to move stuff around or not. Maybe we'll move Valor to Thursday that [week]."

Why the change? | According to Pedowitz, everything came down to scheduling. "Last year's crossover was the most successful week, I believe, in CW's history in terms of the ratings and all that goes with it," he said. "We felt if, as is the case, we already have Flash and Legends paired, that it would be better and tighter in terms of storytelling if we make them two two-hour movies or miniseries. From that point of view, we felt like this was the best way to go. We've had a lot of conversations with the executive producers, the studio, our scheduling people, and we thought this was a tight, concise way to do it. And next year, we may go back to four nights."

Bigger than ever | Although last year's event was billed as a four-show crossover, it actually only took place over three episodes, with Supergirl introducing the crossover in the final moments of its episode. But this year's crossover has officially upgraded. "It's a full, four-episode crossover across the board," said Pedowitz. "This will be even bigger."

New intel | How are they going to top last year's alien invasion? Details are still being kept under wraps, but Pedowitz did offer a few inside details. "Romance is in the air," he said. "The crossovers will definitely have a purpose." Added Legends and Arrow executive producer Marc Guggenheim: "There's no way that we can top aliens last year, so let's up the emotional content. I'm not saying the emotion is romantic, necessarily. We wanted there to be some really big emotional turns for our characters. One of the differences about the crossover this year, as opposed to years past, is, we're doing some big character moves that affect all four of the shows."

Executive producer Greg Berlanti, appearing at TCA for an Everwood reunion panel, elaborated a bit more about what to expect. "Our way of making the show bigger this year was to go even more personal. It's a big life event for a few different people on the show." A big life event, like a wedding, perhaps? "There are many life events that happen," he said with a laugh.

Gotham 

Check your DVR | Gotham fans don't actually have to wait for new episodes as long as they expected. Fox has moved up the season-four premiere by a full week. The Gotham premiere, originally slated for Sept. 28, now airs Thursday, Sept. 21, at 8 p.m., so check your DVR and make sure you don't miss out.

Grundy is coming | Confirming suspicions teased in the season-three finale, Drew Powell is officially turning his former henchman, Butch, into DC Comics zombie supervillain Solomon Grundy in season four. The actor tweeted a video showing his physical transformation after training hard in the gym to get into peak shape.

The Flash

A new ally | With a whole new slew of villains set to make Barry Allen's (Grant Gustin) life hell in season four, at least he'll have one new ally by his side. The Flash has cast Hartley Sawyer as Ralph Dibny, aka classic DC Comics character Elongated Man. The recurring role is described as "one of the Flash's most iconic allies." The Elongated Man is a fast-talking PI with investigative skills that rival those of Batman. Upon discovering he has the power to stretch his body to any shape or form, Dibny uses his new abilities to help Team Flash solve one of Central City's greatest mysteries.

Arrow

Two confirmed survivors | While Guggenheim wouldn't reveal how many people survived the Lian Yu island explosion in the season-five finale, he did confirm that both Canaries do survive. "Both Laurel [Katie Cassidy] and Dinah [Juliana Harkavy] survive," he said. "Spoiler alert: We didn't kill off everyone except for Oliver [Stephen Amell] and one person. He still will have a team, but the question is, what is the composition of that team, and how were they all affected by the trauma of what happened in the past year? It's more than who lives and who dies."

Legends of Tomorrow

Girl power | New Legends team member Zari (Tala Ashe) was added to the show because "we all recognized that there weren't enough women on the Waverider, and that's something we've been looking to address," Guggenheim said at TCA. "We were talking about bringing on a female character and what her powers would be. You might have heard there was this election. Not to get political, but something we all gravitated toward in the writers room was the idea of the character being Muslim. That was very important to us — not to make a political statement, but one of the things we pride ourselves on across all the shows are someone's race or religion or sexual orientation is not the only aspect of their character. My sister-in-law is Muslim, and talking to her, I realized how difficult it is to be a Muslim-American in the current political climate. Along with being a computer hacker and being a superhero and being from the future who also happens to be Muslim the way other characters happen to be Christian or the way that Felicity Smoak [Emily Bett Rickards] on Arrow happens to be Jewish, it's a nice, important aspect of her character."

Changes from the comics | While comic book fans may recognize Zari's name as DC Comics alter ego Isis, Legends of Tomorrow won't be referring to her by that name at all for a very specific reason. "It's pretty simple, really," said Guggenheim. "You might have heard, there is this terrorist organization called ISIS, and they're ruining things out there in the world. We just didn't want the baggage, quite frankly, especially given the fact that we are doing a Muslim superhero; it was just like opening up a can of worms. It's just not worth it."

New (old) villain | The Legends will find themselves going up against a group of villains this year much like last year's Legion of Doom, led by former Legion member Damien Darhk (Neal McDonough). And one of the new season's villains will be familiar to The Flash fans. "One of them is Gorilla Grodd," said Guggenheim. "It's a post-Gorilla City Grodd. He'll be part of this group of villains. We're going to have a group of villains that's going to have more of a rotating membership than we had last year. We want to give you the sense of a group like we had last year because that was a lot of fun, but there'll be a little bit more rotation so we can give you a little more variety, in terms of bad guys. I have a name for them that I would love to see referenced on the show. I shouldn't say it just yet."

Going back to the beginning | In an upcoming episode, Legends will explore Ray Palmer's (Brandon Routh) childhood, and that will uncover a shocking history behind the team's sunniest, most optimistic member. "We get under his skin a little bit, and we get behind his pathology of optimism," said executive producer Phil Klemmer. "There's a bit of sadness to his childhood, and you realize he's hiding some darkness."

What do you think of all the shocking twists and reveals from the DC Comics series? Let us know your thoughts in the comments section below.

Gotham returns for season four on Fox in the fall; Supergirl will return for season three on The CW in the fall; The Flash will return for season four on The CW in the fall; Arrow will return for season six on The CW in the fall; and Legends of Tomorrow will return for season three on The CW in the fall.