With the current explosion of DC Comics-based shows on TV, a whole slate of them -- "The Flash," "Arrow," "Legends of Tomorrow," "Supergirl," "Gotham" and "Vixen" -- got the spotlight on the Saturday night "Warner Bros. Television and DC Entertainment Screening Block" panel, a three-hour event inside Hall H at Comic-Con International in San Diego; featuring both screening of new footage and cast Q&As.

The panel began with "The Vampire Diaries" star Ian Somerhalder introduced as master of ceremonies, followed by a short "Arrow" season three video -- before Stephen Amell took the stage in full costume (specifically, the recently revealed season four costume). "San Diego Comic-Con, you have not failed this city," he told the crowd. Speaking in character, Amell said he -- well, Oliver Queen -- has "lost people forever." "But Star City -- not Starling City -- still needs heroes."

"All of you have come so far, and I ask you come a little bit further -- with the Green Arrow," Amell said.

This led to a longer "Arrow" season three highlight reel, before the introduction of the cast --Stephen Amell (Oliver Queen/Arrow), Katie Cassidy (Lauren Lance/Black Canary), David Ramsey (Diggle), Emily Bett Rickards (Felicity), Willa Holland (Thea), John Barrowman (Malcolm Merlyn), Paul Blackthorne (Quentin Lance); executive producers Greg Berlanti, Wendy Mericle, Marc Guggenheim and Andrew Kriesberg; plus DC Entertainment Chief Creative Officer Geoff Johns.

"We've always said the progression for Oliver is from Arrow to Green Arrow, and this is the next step," Berlanti said, adding that the show is more about who he's going to become than who he was. Kreisberg added that Oliver is in much better place when season four starts -- "He's happy, he's in love. I think that feeling infuses all the character." There will be a little more humor on the show, but "still shooting arrows, still scenes in the rain."

Earlier this week, Neal McDonough was announced as villain Damien Darhk, as major part of "Arrow" season four. "There's another big [villain] coming beyond Damien Darhk," Johns said, "There's a lot of characters coming up that people won't really guess that will appear soon."

Guggenheim confirmed two more DC Comics characters that will be introduced in "Arrow" season four: Anarky and Mister Terrific.

"He's got to work with Felicity," Berlanti said. "Our version of Mister Terrific happens to be gay."

Holland will be in a red leather costume as Speedy in "Arrow" season four. "I had tears of joy when I tried on the outfit for the first time," Holland said, adding that it's a rare example of a female character in pop culture suffering trauma but coming out stronger on the other side.

Barrowman said he's not sure if he's keeping the hooded look or taking on the Ra's al Ghul robes. "You're going to get back into the hood for episode three," Guggenheim told him.

Ramsey was asked if he'd be keeping his facial hair he's currently sporting -- his "hiatus scruff." "I don't know if it'll go with my new helmet," Ramsey said, as Diggle now "officially" has a costume. "Yeah," Ramsey said. "It's called 'Black Driver.'" Guggenheim said that Diggle has taken Oliver's advice to protect himself, especially now that he has a wife and daughter.

Amell and Rickards were asked about "Olicity" being named "Ship of the Year" at the MTV Fandom Awards. "It means a lot," Amell said. "Not quite an Emmy, but it means a lot." "You guys are the best fandom," Rickards added. "Sometimes it's hard to articulate or respond because it feels distant, than we get here, and the love is apparent."

First fan question: Will Oliver be more sarcastic and "silly," like the Green Arrow of the comic books? "I did just ask everyone to follow the Green Arrow, so I think we are going to move into a more Green Arrow-y direction," Amell answered.

A fan asked about new character dynamics in season four. "Everyone knows everyone's business now," Amell replied, referring to the main characters' secret identities now all being known to each other. That will lead to fresh dynamics being explored -- such as Malcolm & Felicity and Laurel & Thea.

That wrapped the "Arrow" portion of the evening's program, with "The Flash" up next.

"The Flash" portion focused on a season one recap, along with plenty of hints for season two -- including a voiceover stating, "My name is Jay Garrick, and your world is in trouble," and ending with the text "Zoom is coming."

On the "Flash" panel: Kreisberg, Berlanti and Johns; plus cast members Grant Gustin (The Flash/Barry Allen), Candice Patton (Iris West), Danielle Panabaker (Caitlin Snow), Carlos Valdes (Cisco Ramon), John Wesley Shipp (Henry Allen) and Tom Cavanagh (Harrison Wells).

"Our 'Big Bad' this season is going to be Zoom," Kreisberg said. "He's going to be faster than the Reverse-Flash, faster than the Flash, and it's going to be very hard to catch him." Kreisberg confirmed that Teddy Sears will play Jay Garrick in "The Flash" season two, and Shantel VanSanten will play Patty Spivot. Also coming to "The Flash" season two: Wally West, though no casting was announced.

While not named beyond "Zoom," the character is likely Hunter Zolomon, a character created by Johns and Scott Kolins introduced as Zoom in 2003, with a name inspired by "Professor Zoom" -- another alias of the Reverse-Flash, Eobard Thawne, the main villain of the first season of "The Flash" (played by Cavanagh).

"This year we're going to be introducing characters from Earth-2," Berlanti said. "That's obviously the origin of Jay."

Starting with Gustin, the series lead said much of Barry Allen's arc at the start of season two will deal with him getting more attention as The Flash, while knowing that the late Eddie Thawne was the real hero in stopping the Reverse-Flash.

Turning to the major developments surrounding Cisco near the end of season one, Valdes said, "Cisco starts seeing these visions, having these dreams. He starts undergoing these biological changes, and those kind of augment themselves over time." The beginning of season two will see Cisco dealing with these changes. "Changes in his body for sure," Valdes added. "Though not puberty. Though he does look 12."

"Jay Garrick is obviously integral to the Flash mythology," Kreisberg said of the original Flash. "Now that we've established our Flash, we thought it was interesting to bring on the original Flash, and create a brand-new episode for Barry to have." Johns pointed out the episode number of last year's season finale which had the first appearance of Jay's helmet was "123," the same as the issue number of "The Flash" comic book where Jay first met Barry (the famous "Flash of Two Worlds" story).

Patton said that Iris will have a lot more "agency" in "Flash" season two, and she's already filmed multiple scenes in STAR Labs since returning from hiatus. Patton also said Iris will bring her "knowledge of the streets" to help Team Flash.

Cavanagh was asked about viewers seeing the "real" Harrison Wells in "Flash" season two. "Last season was absolutely tremendous," Cavanagh said. "The writers did a tremendous job fashioning a character that got to play good and bad, and we're interested in continuing that kind of duality in season two."

Panabaker was asked about the first season finale's glimpse of Caitlin Snow taking on the villainous Killer Frost identity as The Flash raced through the Speed Force. "We worked really hard on that look," Panabaker said. "I'm excited to see her more often, hopefully."

The first question asked about villains for season two. "Gorilla Grodd will be back. We have a big Captain Cold/Golden Glider episode early on," Kreisberg said. "We've got a couple villains we don't want to share, yet. We're really excited about Zoom -- how that presents, the challenges he brings to our characters. He's going to be terrifying, and scary, and fast."

A fan delivered a very direct question: "Will Cisco become Vibe next season?" After a few non-answers, Johns pointed out that he and Kreisberg wrote a "Vibe" series for DC Comics, which explained how the character's powers worked with the multiverse.

That was it for "The Flash," moving straight in to "Legends of Tomorrow." A quick video showed some new footage, with cuts to comic book-y art of the individual main characters. That led to the previous released trailer for the series.

Johns served as moderator for the "DC's Legends of Tomorrow" Q&A, featuring Berlanti, Guggenheim and Kreisberg along with fellow executive producers Phil Klemmer and Sarah Schechter; plus cast members

Ciara Renee (Hawkgirl/Kendra Saunders), Victor Garber (one-half of Firestorm/Dr. Martin Stein), Brandon Routh (The Atom/Ray Palmer), Wentworth Miller (Captain Cold/Leonard Snart), Caity Lotz (White Canary/Sara Lance) and Dominic Purcell (Heat Wave/Mick Rory).

Guggenheim told the crowd that the first few episodes of the new seasons of both "Arrow" and "Flash" will contain some "table-setting" for "Legends of Tomorrow" -- including revealing to the world that Ray Palmer survived the "Arrow" season finale explosion, and reviving Sara Lance from the dead.

Johns revealed that along with Hawkgirl, Hawkman will appear in "Legends of Tomorrow." No casting was announced.

Lotz commented on her character's reaction to being resurrected, and pointed out that no one comes out of the Lazarus Pit the same way they went in. "There are consequences of that," she said. "We'll see what happens when she comes back to life. She was already pretty crazy. Now, after that -- I want her to go just nuts, off the rocker. That's my plan."

Johns asked Miller about Captain Cold's unlikely position on a superhero team. "There is no altruistic bone in his body," Miller said of Snart. "I'm not sure he's totally down for [being part of a team], but that's where the fun is. These guys have to work together, and it's going to be a bumpy ride."

Pointing out Kreisberg's "Doctor Who" fandom, Johns asked the executive producer about the time travel element of "Legends of Tomorrow." "We keep talking about how on 'Arrow' and 'Flash,' we come up with an idea, but say, 'it's too crazy,'" Kreisberg remarked. "'Legends of Tomorrow' is just the crazy stuff."

Discussing how Dr. Martin Stein fits in, Garber said that his character is arrogant enough to think he can "[mediate] this dysfunctional family." "He does have high ideals, and is naive enough to think that this could work," Garber said. "We'll see how he does. I'm confident that he'll make it. Firestorm will definitely be a part of it -- probably more than I even realize."

Renee said to prepare for the role of Hawkgirl/Kendra Saunders, she's read comics, watched all of "Flash" and "Arrow" and has been training in boxing and martial arts. She also expressed excitement for the repeatedly-reincarnated aspect of the character. "It's going to be interesting to see her in these different time periods," she said. "As an actor, it's an incredible challenge. I get to play different people."

Berlanti thanked the fans for making a show like "Legends of Tomorrow" -- a DC Comics-based superhero team-up show, something that would have seemed improbable in another era -- happen.

Johns asked Routh what keeps drawing him to superhero roles. "I don't know if I find myself drawn or if something else is drawing me to it, but either way I'll take it," Routh said. "It's a magical world full of possibility. That's what we do in film and television, and this is such a heightened version of it."

Next question was to Lotz, asking why White Canary is the most dangerous member of the Legends of Tomorrow. "She's not afraid to die," Lotz said of White Canary. "She's died multiple times. Imagine that. Imagine you have no fear of death -- every situation that you go into, there's this reckless abandonment you can have."

Johns asked Klemmer, who recently worked on "The Tomorrow People," about what attracted him to "Legends of Tomorrow." "That was one of the easier decisions I've ever made," Klemmer said. "Being able to return to the Berlanti family; I've spent my entire career at Warner Bros. To be able to do something like this, with a cast like this, really was a millisecond sort of decision."

Next up: "Gotham." The presentation started with a lengthy video recapping the first season, leading into a new, brief look at season two.

On the "Gotham" panel: Johns, executive producers Bruno Heller, Danny Cannon and John Stephens; plus cast members Ben McKenzie (Jim Gordon), Donal Logue (Harvey Bullock), David Mazouz (Bruce Wayne), Sean Pertwee (Alfred), Robin Lord Taylor (Penguin/Oswald Cobblepot), Camren Bicondova (Selina Kyle), Erin Richards (Barbara Kean), Morena Baccarin (Leslie Thompkins) and Cory Michael Smith (Edward Nygma).

"This season is bigger, more colorful, more intense, more exciting," Heller said of "Gotham" season two.

Johns said he knew right away that Heller had a vision for "Gotham" when he pitched the idea that Selina Kyle witnessed the murder of Bruce Wayne's parents. "There are more stories told about Batman than any other character, ever," Johns said. "You need someone like Bruno to give it a new spin."

"There will be no heroes introduced on the good guys' side, and they'll have to band together to fight the villains," McKenzie said of "Gotham" season two. Speaking of his character's relationship with Logue's Harvey Bullock, he said there's a "mutual respect," and what he predicts, "a partnership for years to come."

"Jim Gordon reinvigorated Harvey Bullock," Logue said, yet by the end of season one, "I think Harvey Bullock's really old and tired and beaten. At this stage, when he find Harvey in season two, he might be beaten down. He might be a little less idealistic than Jim Gordon about our chances to stem the tide of the bad that is coming."

Richards was asked about the relationship between Jim and Barbara as season two begins. "The relationship between me and Jim has changed quite a lot, because I killed my parents, and he's a police officer," Richards said. "So it's strained, to say the least."

"She's the crazy ex-girlfriend from hell, but it's also the story of fulfilling your potential," Heller added. "It's just crazy potential."

Pertwee said in season two, viewers will see "more of an adult relationship" between Alfred and young Bruce, with "mutual respect and understanding." Mazouz said they'll experience something of a "rocky path" before becoming part of the same team.

Cannon said season two of "Gotham" will see the birth of even more villains.

Taylor was asked where his character will be when "Gotham" season two begins. "He's achieved his goal," Taylor said. "He's the king of Gotham. He spent the whole first season laying the groundwork. He knows that once you reach the top, there's someone right there, ready to take you down. He's prepared to fight to stay up there."

As an audience member was about to ask a question, Cameron Monaghan came out of the audience in character as Jerome, the likely future Joker. He snatched the microphone away from the fan and asked, "How high is your pain tolerance?" before being stopped by security. "I'm going to find you Jerome, and I'm going to take you down," McKenzie said from the stage.

With that, the "Gotham" section wrapped, and Somerhalder asked, "Who was that? He looked like the dude from 'Shameless.' I guess everyone's a Joker these days."

On the "Supergirl" panel: Series star Melissa Benoist; fellow cast members Mehcad Brooks, David Harewood, Chyler Leigh and Jeremy Jordan; plus executive producers Ali Adler, Sarah Schechter, Andrew Kreisberg and Greg Berlanti; and, once again, Geoff Johns.

Adler said that "Supergirl" was a "story that needed to be told. You'll go into it seeing her as 'female,' and leave seeing her as 'powerful.'" Johns said that it's important for women to be involved in the production of every show, not just "Supergirl."

Adler spoke of the casting of Benoist as Supergirl. "We saw thousands of women, and this was the first one we saw." Kreisberg pointed out that's not the first time it happened -- Stephen Amell was the first actor they saw for "Arrow," and Grant Gustin was the first actor they saw for "The Flash."

Contrasting that, Benoist said, "I remember leaving my first audition saying, 'I blew it. That was terrible.'" Harewood said that viewers will have to wait and see if his character, Hank Henshaw, is a good guy or a bad guy.

Adler revealed two villains who will be seen in "Supergirl" season one: Reactron and Livewire. Also joining the show: Maxwell Lord, as played by Peter Facinelli, who then joined the panel.

Kreisberg said the show is heavily influenced by Richard Donner's "Superman," and aims to "bring light into the world." Following the conclusion of the "Supergirl" Q&A, a modern dance troupe performed on stage, leading into a screening of the "Supergirl" pilot.

Keep reading CBR all weekend for the latest from Comic-Con International!