User blog comment:Master Sima Yi/Assassinews 03-03-'13 — Assassin's Creed IV: Black Flag trailer and screenshots/@comment-4705174-20130305000524/@comment-4975789-20130305170152

I hope they are comrades but not necesserily allies. So you meet, and talk to, Blackbeard during the game, but you don't fight with or against him.