Since Eren wants them to fight and how plot is evolving, the aim of Eren is get killed by his friends. So, he became a monster that will genocide the entire planet just to force the planet to unite with eren's friends and let them kill himself.
So, Eren's goal is to get killed while he try to destroy everything by his friends, and his friends goal is just killing Eren.. I would be so surprised if Eren survive at the end, cuz the goal is showing the world that people from the island are heroes and they are people with same value than others and not demons.
Create a final boss to unify two factions. And I think that Armin knows that, since Eren talked to him saying that the only way is fighting not talking, he is smart enough to see that Eren is bluffing with his plan and the real plan is getting killed by Armin and Mikasa