I don't get why Vince would have a dark, mysterious ad. He is not known for having the slightest air of darkness to his returns. It HAS to be for Taker or Jericho (or STING!!!
We know Kane is coming back masked, so this promo wasn't for him. Unless it's the WWE debut of a prominent wrestler in other companies (not signaling out Sting, but perhaps a new version of the NWO).