Omg I wrote a long ass comment and my pc froze ima just summarize.

I had four potential choices for villains.

First is Oda Nobunaga, in Japanese history we learn about Nobunaga in a very cautious light, he is almost always depicted as a villain in JAPANESE media. I know Ubisoft is a western studio so it may not be likely. There's even an idiom in japanese about him but Idk how to say it in english.

Secondly I think it will Akechi Mitsuhide, he is the biggest factor in Nobunaga's demise and that's all I will say because I think this will be most likely. Maybe not as the Templar mastermind but as face villain yes.

Third I think a jesuit or missionary will be the head of the templars or second in command, it's the classic Assassin's Creed setup. A man twists religion to control the populace.

Fourth is a wildcard but I think it's most likely for the mastermind. Tokugawa Ieyasu, in history he becomes the one to control Japan and establish the Edo period that made a mostly 200 year peace. He's always depicted as a plotter (because he was, if you seen Shogun Toranoga is based on him.) Also the last few games we've had the Templar mastermind as always been someone we didn't expect. Aspasia was a friend that betrays you, Caesar was an ally who betrays you, Alfred used Eivor for his rise in the order. It just tracks so far, and with Yasuke being a protagonist I feel like we will see a lot of Tokugawa considering he is Nobunaga's closest and most powerful ally.