User blog comment:Master Sima Yi/Assassinews 19-03-'14 – Two Assassin's Creeds for 2014?: Unity and Comet/@comment-4999424-20140612174409/@comment-1379990-20140612183850

In a way they could still be new characters. Remember the multiplayer characters in the former games often made an appearance in the singleplayer, so it might be possible that you will see them in the singleplayer in some form.