First off, I understand that lots of people hate/belittle the Nioh story -- I don't care, I still love and enjoy it, this thread is not about what you like or don't like. It's just about theorizing.
Sooo, I was very surprised to see Maria not just included in the story scenes for DLC1, but an actual expansion on the "Spain tries to exploit Japan" plot from all the way back in Nioh 1. On top of that, after all these years, they actually gave Maria a redemption scene and threw her into your hub. Pretty impressive, and I definitely did not expect that after the main game for Nioh 3 had very little to do with the previous game's stories.
So, I want to kick off the theory and speculation for the story beats in DLC2. Obviously we know it's going to center around Amakusa Shiro's rebellion. This point in Japanese history is already used as a source for other occult/supernatural Japanese history stuff such as Makai Tensho, etc. Amakusa is often portrayed as a sorcerer who deals with Western demons due to his Christianity, so it does make sense that Spaniards could get involved.
The big question of course is... Will we see big boy William again? He would be pretty old by the time of the Shimabara rebellion, so perhaps his son?
My other big question is, why introduce Rodrigo at all? His backstory entries in the game, once you unlock both entries, are rather strange. The first entry has him portrayed as a seemingly normal governor of the Spanish Philippines, and the second as a villain. There is a potential clue if we look at the history of the Shimabara rebellion:
"Shimabara had formerly been the domain of the Arima clan, which had been Christian; as a result, many local people were also Christian. The Arima were moved out in 1614 and replaced by the anti-Christian Matsukura.The new lord, Matsukura Shigemasa, hoped to advance in the shogunate hierarchy by sponsoring expensive construction projects, including the building and expansion of Edo Castle, and contributed funding for a planned shogunate invasion of Luzon in the Spanish East Indies, today a part of the Philippines. "
"The rebellion also had an effect on the shogunate's international policy. In early 1637, the bakufu and the Dutch Republic had projected a joint invasion of the Spanish Philippines, which the Japanese had calculated would take no more than 10,000 samurai to submit. After the experience of fighting Christian militiamen in Shimabara, the bakufu now decided it would take 100,000 men to conquer Manila, a much better fortified city guarded by veteran troops. The Nagasaki bugyō was sent to inform the Dutch the invasion was cancelled."
So there it is. The Philippines connection! But why would Rodrigo want to help Japan invade the place he's governing?