Eren Yeager is the main character of Attack on Titan and has changed a lot over the years. When he was first introduced, he wanted to become a member of the Survey Corps, feeling that they are the only people around him that are admirable. After the Titans broke into Shiganshina, followed by Wall Maria, and his mother died, he joined the military and his dream came true after he graduated.
For a long time, the series would follow Eren and his friends on their adventures as soldiers. However, after a time jump, fans saw that Eren's beliefs, personality, and relationships had greatly changed. In fact, most fans like him even more towards the end of the series than they did in the beginning.
10 Has Grown: He Doesn't Care About Killing Titans Anymore
Eren wanted to join the Survey Corps so he could go outside the walls and kill Titans. Even before the Colossal and Armored Titans broke into his home, he was determined to leave the country that he thought of as a prison, wanting to be free. Once tragedy struck, however, his anger and determination increased.
He swore that he would kill every Titan and kept this mindset until he learned the truth about them. Nearly every Titan that he was fighting was an Eldian that had a serum injected in them that turned them into the predators of humanity. This was an attack from Marley, the enemies of the Eldians. Once Eren knew this, the Titans no longer felt like the threat he believed they were.
9 Hasn't Grown: He Still Wants To Defeat All Of His Enemies
After learning about the Marleyans, Eren knew who his enemies really were. His rage was directed towards any country that wanted to harm Paradis, and he would hurt them even more than the Titans.
Eren began The Rumbling, the greatest attack the world had ever known. All of the Colossal Titans that were used to create Paradis' walls unhardened and Eren used them to stomp on all of his enemies. A blade to the neck was nothing compared to having every bone in one's body be crushed.
8 Has Grown: He Overthrew The Military
Eren used to have a lot of respect for the Survey Corps and was an important figure to the military as a whole. Nobody ever thought that he would end up overthrowing it and turn on his former comrades.
However, once he started working with Zeke, Floch, and Yelena, he killed Darius Zackly, the general of all three branches of Paradis' military, and betrayed the people that he had survived many battles with. Having this new power allowed Eren to do anything that he wanted in Paradis, with nobody being able to stop him from taking over.
7 Hasn't Grown: The Eldians Still Have Faith In Him
After the Eldians learned that Eren was a Titan shifter, they felt like they had the ultimate weapon. Some had hoped to use him and thought he was their greatest ally, while others feared him. Throughout the years, Eren proved many times that he was needed.
One of the reasons why he was able to overthrow the military was because he had a lot of followers, the Yeagerists, to help him do so. Though the Survey Corps were no longer on his side, he didn't need them as there were other soldiers, as well as civilians, who believed that he had the right to do anything he wanted and would follow him down whatever path he wanted Paradis to go on.
6 Has Grown: He Has Become Much Stronger
Eren has gotten much more powerful through time. Not only did he learn how to control his Titan better, but he also inherited the War Hammer Titan, giving him even more abilities. As he was also able to control The Rumbling and bring the previous inheritors of the Nine Titans back to life under his control, he became the most powerful character in the franchise.
He could have even controlled all of the Eldians if he wanted to, which would have made him even stronger, but he didn't want to take away their freedom.
5 Hasn't Grown: He Hasn't Lost Any Of His Powers
When a character gains a lot of new abilities, they don't use their older ones as often, and eventually not at all. It's been seen with a lot of fighters in anime, and all other stories. However, he had the Founding Titan before he even joined the military and continued using it by the end of the series
Up until The Rumbling, he also fought all of his battles directly, using the Attack Titan as well. All of the Titan's abilities are close in strength, making them all pretty useful, and Eren used them all to the best of his ability.
4 Has Grown: He Is A Lot Calmer Now
Ever since he was a child, Eren was very aggressive and sensitive. He'd easily get into a fight with anyone that had a different opinion than his. He'd also act very recklessly, not thinking much.
However, once he started seeing the future and knew things that were going to happen before they did, his personality changed. He became much calmer, rarely showing any emotion. He also got darker and more serious, causing the people that were closest to him to not feel like they knew who he was anymore.
3 Hasn't Grown: He Still Cares About His Friends
Despite turning his back on them, everything that Eren has done was to protect his friends. This is why he didn't take away their freedom even though he easily could with the Founding Titan.
He simply wanted to give them the best lives they could have and needed to betray them in order to do achieve this goal. Because of his actions, many people around the world no longer want to fight with the Eldians, decreasing the hatred and discrimination that went on for nearly 2,000 years.
2 Has Grown: He's Become The Antagonist Of The Series
A lot of fans debate on whether Eren is the hero or the villain of the series. Some of them support his actions and can be called real life Yeagerists. Others think that he was wrong and went too far.
However, seeing as how the story began to revolve around other characters like Mikasa, Armin, Reiner, and Annie once The Rumbling began, Eren was not the main character of the War For Paradis arc, but rather the antagonist of it. He wasn't seen as much as he was in previous arcs and barely said anything compared to a lot of the other characters.
1 Hasn't Grown: He Was Always The Person He Became
Once Eren and Zeke went inside of the coordinate, it was revealed that they weren't actually on the same side. In a final attempt to convince his younger brother that their father brainwashed him, Zeke showed Eren Grisha's memories. One of these memories was when Grisha stole the Founding Titan from the Reiss family.
He had hesitated to do so before this future Eren convinced his father to go through with it. Shortly after, Grisha gave the Eren from his time period both the Founding and the Attack Titans. Because of this, Eren set his past self to go on the path that he went on, knowing who he would turn out to be.