I feel like this show makes a point to go in directions that literally no one can predict, yet it somehow always works. After just dumping all that info on us at the end of Season 3, we now get dumped into an entirely new world and have to try to navigate our feelings about what we're seeing and learning.
Having Eren show up was a huge surprise, and I was even more surprised that he revealed himself to Reinhar. What is the goal here, if not the element of surprise? They clearly don't expect anything like this, islanders appearing on the mainland. Why isn't Eren's leg growing back? And why haven't we got to see Colossal Armen yet???
PS - I remember where the Attack Titan came from now, it was that guy who had infiltrated the Marllian army and Grisha ate him. I forgot 🤣