The original leak of Assassin's Creed Unity came alongside word of a last-gen (PlayStation 3 and Xbox 360) game, which so far hasn't materialized. Even after E3, the so-called "Assassin's Creed Comet" is still purely in rumor territory, but that could be changing soon.
IGN reports that during an investor call today, Ubisoft CEO Yves Guillemot responded to a question about an Assassin's Creed game for the older platforms. "More info on that soon," he said. "It will come soon."
Tony key added that Ubisoft hasn't "forgotten about [their] loyal Assassin’s Creed fans on those systems.”
According to the original rumor, Unity was to be the new-generation Assassin's Creed game set in Paris, while Comet was to be last-gen only and set in North America. This would allow Ubisoft to take full advantage of both systems rather than forcing it to develop cross-platform. We had expected Comet to show up at Ubisoft's presentation at E3, but only Unity appeared. That means half of the original rumor panned out, and waiting for the rest has most likely just been a matter of time.