User blog comment:Master Sima Yi/Assassinews 28-02-'13 — Assassin's Creed IV: Black Flag revealed/@comment-3046679-20130228120814/@comment-217.209.115.197-20130228144300

Well, it's not really that strange, Ubisoft gives the games a new number when a new character appear, Aveline was an exception due to the fact that Liberation was only released on the Playstation Vita.