Looks like Black Flag was teased in Assassin’s Creed III

Assassin’s Creed III contains a reference teasing what would be the next entry in the series, Black Flag. At one point in the game, Connor mentions that sailing runs in his family and how Edward Kenway – the star of Assassin’s Creed IV and Connor’s grandfather – “sailed with a rough crew”. Take a look at the video above for the pertinent scene.

Source