When Warner Bros. Television revealed the first look at "Arrow's" third season on Friday, it was holding back something big: the identity of the primary antagonist.

A new version of the trailer, screened Saturday during the three-hour "Night of DC Entertainment" at Comic-Con International, ends not with the "Arrow" logo on a black background but with the introduction of Ra's al Ghul. Or at least his lower-half.

"If half of the stories I've heard about Ra's al Ghul are true," Stephen Amell's Oliver Queen says in voiceover, "we will all pay."

The CW drama has been building toward an appearance by the DC Comics villain for a while, beginning with Malcolm Merlyn's mention of Nanda Parbat in Season 1. In the second season Ra's al Ghul was an invisible hand operating off-screen, sending first a team of assassins and then his daughter Nyssa to bring back Sara Lance (aka The Canary, who was trained by the League of Assassins).

"It really happened very organically in the sense that we had this notion that in Episode 16 we were going to reveal that Malcolm Merlyn was trained by the League of Assassins and that's because of the comic book," executive producer Marc Guggenheim told a group of journalists Saturday. "We were like, you know what we're going to do? We're going to get away with a little reference about a guy in Nanda Parbat who changed his life. That was just the beginning."

Casting is under way for the role of Ra's al Ghul, who will appear early in Season 3. "Arrow" returns Oct. 8 on The CW.