Eren Cared More About Freedom Than His Friends and Family
I just want to say this for anyone that thinks Eren is a hero. He genuinely desired to destroy the world (which put his friends in danger and got some killed) more than protecting his friends. The real reason the Rumbling happened is because he wanted to see a flat, empty world devoid of life. This was his childhood dream of freedom.
He tells Ramzi what he tells himself to justify the Rumbling. Saving the island, saving his friends, etc. But then he admits the actual real reason; he was disappointed that humanity lived outside the walls. He later admits to Armin that he didn’t do the Rumbling for his friends but instead did it because he wanted to see the sight of a flattened world. It is his childhood dream which is why he regresses to his child-self when his dream is actively being fulfilled in the Rumbling. He has achieved his “freedom” which he desired above the safety of his friends.
Obviously Eren felt guilty over this and looked for any way possible to change his future (he thought he might be free of the future a couple times such as when Willy Tybur says that he “was born in this world”). But in the end he realized that this future was only happening because he wanted it to. And it wasn’t for the safety of the island or his friends. It was for his dream. Eren did genuinely love Armin and Mikasa and he loved his friends. He wished that he could distract himself from his dream, whether it be to run away with Mikasa or to find another possible future, but he ultimately can’t. Eren could’ve followed the small-Rumbling plan with the 50 year modernization, but he didn’t. He wanted to go full genocide and destroy the world, regardless of the safety of his friends. Eren knew that what he was doing was wrong but it couldn’t overpower his drive for freedom and “that sight.”
It’s why he says he’s the same as Reiner. They both had deeper selfish motivations to do horrible things than what they outwardly portrayed to others. And Eren wanted to be judged before committing to an act, like how the refugee wanted to be judged before dying, like how Reiner wanted to be judged before wanting to die. Eren wanted to be judged by Reiner. He’s seeing himself in Reiner and Reiner’s words are both judging himself and Eren. Eren wanted to be judged and confront his own guilt before committing to the terrible future he saw and is the cause of.
Eren is a full-on villain. You can call him a tragic villain if you’d like but I’d say that he’s just a genuine regular villain who had this awful nature to begin with. The entire series shows us his perspective so we can understand him and see his worldview. We spend the whole series sympathizing with him only to see what that sort of worldview and mindset can lead to with massive power.