Eren is willing to make hard sacrifices.
Most of Attack on Titan's usual protagonists are nowhere to be seen, but a long-haired, injured Eren Jaeger has managed to infiltrate this foreign land under the guise of a recovering soldier.
Nevertheless, the character has typically proven popular within the Attack on Titan fanbase.
Morality in isn't black nor white, but more increasingly depressing.
If that's the direction the anime is going right now, then Eren's plan may or may not be to paint himself as the main villain so that the world can unite against him and be at peace for a while.
As a result of the experiment, the Ackermans possess the power that can match a Titan Shifter in their human forms.