We went straight to the source to learn everything we could about Assassin's Creed IV Black Flag and the first thing on our minds was whether a modern-day story would be told to match the arc of Edward Kenyway in the Carribean.
Producer Martin Schelling and Game Director Ashraf Ismail had the answers and they revealed that you would actually be playing as yourself in light of Desmond's finale in Assassin's Creed III. The feud between the Templars and the Assassins isn't over and instead the Templars are attempting a new method of manipulation in the form of Abstergo Entertainment, a subsidiary of Abstergo Industries.
"Desmond's story is over and the new present day hero is you." Schelling explained. "Animus technology has advanced and now you're able to enter another person's ancestral memory." That's how our new present-day protagonist is able to explore the Kenway family's history in the new game.
Edward Kenway is involved in something very important to the Templars and that's why you've been hired to dig deeper into the Carribean narrative. Of course the Assassins will come into play later in the game, but the developers weren't ready to talk about that just yet.