He’s been hinted at in Season 1 and was named dropped in Season 2. You figured with the League of Assassins and his daughter Nyssa showing up, Ra’s al Ghul would eventually appear on Arrow. Thanks to this new trailer, we now know that he is indeed the big bad for Season 3.
The trailer itself may seem familiar to those who saw one yesterday, but do stick around because the Demon’s Head himself puts in an appearance after the previously seen footage. If you haven’t seen any of this, I’ll tell you that it recaps Season 2, shows new footage from Season 3 (including some with Ray Palmer, Count Vertigo, and Arsenal), before teasing Ra’s. Now we don’t see his face, which tells me they aren’t ready to reveal the actor or this was shot with a double. I will say that the character looks closer to his comic book counterpart than what we saw in Batman Begins.
Arrow premieres October 8 on The CW.