It became very clear in Dark Days: The Casting that Batman's latest protege Duke Thomas would have a major role in the upcoming Dark Nights: Metal crossover - and beyond. And at SDCC, Duke's new role came into focus - he'll take on a superhero identity, "The Signal," and serve as Gotham's "Hero by Day," more of a counterpart to Batman than a sidekick.
"I think you guys will be surprised," Metal writer Scott Snyder told Newsarama of Duke Thomas' role, prior to the reveal of Duke as The Signal. "We wanted to try something a little bit new with this one. It has echoes of [Robin], but it's actually something a little bit different that myself and the writer on Batman and a couple of the other writers came up with - a way of sort of spinning the mythology a bit. So we're really, really excited about it."
And according to Snyder, Duke's future will be handled by a newcomer writer - Tony Patrick, who Snyder connected with in his stint as a teacher for DC's Writers Program. The pair will co-write a three-issue Batman: The Signal series with artist Cully Hamner.
"I'd like [Duke] to be a character that we give someone new a chance on - you know, and I'll help with it," Snyder said. "But really try to take a risk with him and try something and see if there's room for somebody who has a different mission, different take, different things.
"You'll hear where we're headed with it at San Diego," Snyder promised - and true to form, he delivered.
Now that we know Duke Thomas's future, it's time to look back at his past and discover how he became the latest member of the Bat-family.
The first time readers met Duke back in June 2013, he was a young boy who helped out Batman during Snyder and artist Greg Capullo's "Zero Year" storyline of Batman. His family even housed Batman when Bruce had just experienced defeat.
And although "Zero Year" took place several years ago - when Duke was just a small boy - he was already showing signs of being a Batman sidekick.
"The first time he appeared in 'Zero Year,'" Snyder said, "he meets Batman in the opening pages… but his actual first meeting with Batman, in the narrative, is when he's trying to solve a crossword puzzle to help Batman defeat the Riddler, to help Bruce defeat the Riddler."
After "Zero Year," most readers probably thought he was a throw-away character, as the Batman title returned to present day.
But the next time he showed up, he was in a "possible" story set five years in the future, wearing a Robin costume and fighting alongside Batman.
"From the beginning, I've been hesitant about the possibility of him becoming officially Robin," Snyder told Newsarama at the time. "I think that he would fit, because of the way he approaches the mantle. I think he'd make a great Robin for that reason.
"But I also feel like… I guess part of me wondered if there was a way to create something new with him as well, so that it would just be another figure in that role, as exciting as that can be."
Duke also showed up in a "vision" Bruce Wayne had, where he imagined Duke wearing the superhero name "Lark" - an identity that Snyder had been teasing for months.
But even before Duke's new identity was revealed, Snyder promised that Duke would find his own niche - something totally different.
"The visions are more about how Bruce thinks things might end for him, rather than any concrete spoilers. But you can get a sense from that moment that Duke is important to him."
During "Endgame," the storyline that saw Batman fighting the Joker, Duke's parents were infected by a new chemical version of Joker's venom. Their disappearance and Batman's apparent death move the boy one step closer to being a full-fledged superhero.
Duke stepped up as a costumed hero after Batman was believed to have died at the end of "Endgame." With the launch of We Are Robin in June 2015, Duke became part of a new concept for Gotham City - a group of teen heroes motivated to fight crime after the assumed death of Batman.
Although Duke Thomas was initially the best-known character in the bunch of new Robins, the story ended up having more of an ensemble approach.
According to Snyder, functioning without a Batman allowed Duke to grow independent of the "sidekick" idea.
"His core belief is that this generation's heroes need to find their own way, to do thing independent of the heroes that came before," Snyder explained. "He's very independently trying to find a place that doesn't make him a proxy or a kind of extension of the family as we've seen it so far."
Later, when it's revealed that Bruce Wayne is alive but doesn't remember he's Batman, Duke Thomas is one of the few people in Gotham City who's "in the know" about Bruce's new life.
Yet it's Duke who eventually confirms to the formerly amnesiac Bruce that he's supposed to be Batman.
By the end of Batman #50, one of Snyder and Greg Capullo's final Batman issues, Bruce Wayne says to Duke, "I have an offer for you." But readers didn't exactly find out what that offer was.
Since then, Duke has been appearing in Snyder's All-Star Batman, particularly in back-up stories about his training. But his official role in the DCU wasn't revealed, and there was certainly no indication that he had any type of metal in his bloodstream.
So yeah, Duke has metal in his blood - something his mother apparently had too. And because of this, they have some sort of connection to immortality and, probably most importantly, to the idea of the light versus the dark.
This was actually teased in All-Star Batman, when Duke Thomas' mother mentions that she visit her toughest legal cases during the daytime.
"[Readers] see pieces of who he becomes, in his superhero identity, coming through [in All-Star Batman]," Snyder said. "Like … about the morning, about the daytime, and that sort of stuff. It was important for his mother [Elaine] to visit the kids that she was really unsure of in the daytime, because she got a better sense of them without the shadows around them, whether they were good or bad or whether they had done the things they were accused of."
Snyder teased that Duke might be the type of hero who doesn't function during the nighttime like Batman, but instead works during the day.
Then in June's Dark Days: The Forge, readers found out that Elaine had the potential to be part of the Immortal Men. In a scene featuring The Immortal Man himself, readers find out that Elaine Thomas had some sort of pre-disposition to be immortal, and that the Immortal Man was going to offer her the chance to join him in "a secret battle" against the dark.
This week, in Dark Days: The Casting, that pre-disposition is further described by The Joker. The villain tells Duke that he was "flagged" as a child because of an unusual metal in his blood - and in the blood of his mother.
"You are the signal," Joker says.
By the end of The Casting, it's clear that the metal inside Duke is connected to the "dark energy" that Batman has been investigating. A dagger made of this metal "does something" to Duke as he can sense something "coming." And using Green Lantern's ring, Duke is able to construct a gateway of some kind to another universe - probably the Dark Universe that Snyder has been promising for Dark Nights: Metal.
When Duke confronts Batman about what the Joker said - that Batman used him as an experiment - Bruce says he only "wanted to be there when you decided what you were going to become." It looks like that moment has come.