Attack on Titan: Is Eren Yeager a Villain or a Hero?

This is the most heated debate amongst the Attack On Titan fandom: Is the protagonist Eren Yeager a Villain or a Hero?

Do not worry, I have not finished reading the manga version of Attack on Titan, so NO SPOILERS for the unreleased second half. 

When a power superior to the power of humans strikes, fear rises which leaves no room for reasoning and the only thing that one can think clearly about is how to put the power down. And Eren knew this very well, he probably was aware that the world will never listen to Eldians and vengeance was the only option left. 

The Journey of Eren from a little bratty kid to the inheritor of the Founder is an emotional, heart-wrenching rollercoaster. A little kid whose hatred towards Titans is rooted from the moment when his mom was eaten by one of them to being the huge monstrosity that might soon ruin the world. 

Eren just wanted to see the beautiful world outside Paradis Island but was faced with hatred and threats to destroy Eldia from billions around the world and his vision of his dream turned into the destruction the world brought upon itself. Eldia, was cornered and a cornered mouse has no option but to attack. 

Throughout the seasons, you might have observed that Eren cared about his comrades and when he found out that Reiner, Bertholdt and Annie are the Titans that led Eldia to this state, he hesitated many times before attacking them. The constant betrayal from them who once fought with Eren shoulder to shoulder made him realize that no matter who is in front of him, he will kill them if they come in between the path towards his freedom. He had to become the devil, that Eldia needed.

Eren just wanted freedom, but the world was not going to offer him that easily without a fight. Infiltrating Marley was the only choice to obtain information and spy on them before the assault on Marley that crippled their military power and that was when Eren started acting upon his own. He knew what was going to happen in the future when he kissed Historia's hand in the ceremony. 

Eren was sure that he will bring the Rumbling and that changed him completely. Eren was sure, that no matter where the Eldians go, they would always face hatred and indiscrimination. The bloodshed will continue and the fact that Eldians and the people of the world will never coexist was clear to him.

The world was bent upon using Eldia as the center of their hatred and launching a war together against Eldia, their only "enemy". Everyone in Eldia knew it well, including Eren and the bottom line is, Subjects of Ymir the race that can turn into titans will always be despised no matter what, as long as the blood of Ymir flows inside their veins, they are no more than a threat to the people of the world. 

As long as they have the power of the Titans, the world will never sit still. He knew he was not going to be that Eren again, that used to laugh and smile with his comrades. He knew it was the only way and he was the only one to give freedom to Mikasa, Armin and Eldia. 

And, therefore, he was ready to sacrifice himself for Eldia and become a villain for the rest of the world. 

The conclusion is that hate is in human nature. Humans love, but they hate passionately. They just need a reason to do so. In this case, they have a good enough reason to leave no room for discussion. The decision's been made, and Eren is left with no choice but to end the world.