is about all of this situation. Eren has been clear in his stance against Marley since chapter 100. He even repeatedly mention how Armin's peace resolution is ridiculous knowing the nature of Marleyan racism and political situation. What he said about Armin is truth that came out of his frustation. The reason Eren went to Marley alone is because none of his friend support his decision to strike Marley to begin with, even Mikasa who show a doubt about it. But you have to know that Armin and Mikasa didn't witness Marley racism, oppression and cruelty like Eren does. Eren sees everything via memories of previous Attack Titan holders. Kruger's parents burned alive, Faye Yeager's murder and Dina's titanization which makes Eren scream and cry back then in his cell. Eren has been burdened with these memories alone. And now time kept getting shorter for Eren's lifespan and Marley political move to declare war on Paradis.

Eren's goal is all to prevent Marley took freedom that Eldian deserved and Shifter generational transfer. I worked his arse off to prevent Historia titanization and force breeding and his own titan inheritence. He wants to stop this toxic cycle. But Armin's plan require Paradis to be safe at least for 50 years which means Historia will be forced to breed and titanize her children like her father does and Eren giving his titan away and burdened other with brutal Attack Titan memories. And in the end we see Historia got pregnant anyways. Eren has lost his battle to protect Historia and this is one of the reason he got cornered and desperate, thus his dark resolution emerge when he met Yelena at railroad celebration. He wants to end this all while he lives. And the peace plan will not let him do so and kept this titan iheritence cycle keep living, something he hates the most.