Eren Yeager

Eren Jaeger (エレン・イェーガー) is the main protagonist of the series. He was from a town of the outer most wall, Maria. His closest friends Mikasa and Armin have both joined the Scouting Legion with him after having their town annihilated by the titans. He holds a personal vendetta against all titans and his goal is to annihilate them form the earth.

Year 844
When Eren was a child, he saved Mikasa from being killed when visiting her home with his father. Three men - killers of her parents - were in her house. Killing two of them, he was caught off guard by the third who proceeded to strangle him. With superhuman strength, Mikasa jumps forward at the man after realizing that it is a "kill or be killed" life they are living. As Eren's father finds them surprisingly safe and unharmed, Eren gives Mikasa the sentimental scarf she always wears, and declared her a part of his family.

Year 845
With the invasion of Wall Maria after the Colossal Titan makes a path, Eren discovers the horrors of the life he is living that sets the motion for his future. Seeing the destruction of his town, mindless titans slaughtering humans, and his own mother being eaten alive as he was helpless to save her, Eren remarks that the life humans live is controlled entirely at the mercy of the titans and are nothing more than cattle. Being dragged away by a local Stationary Troop, Hanneth, Eren swears to kill every single titan in existence with tears of frustration and hatred.

Year 845 to current
After the fall of Wall Maria, Eren, Misaka, Armin briefly stayed in the “landfill” working on a farm before reaching the proper age to enlist in the military. Here they spent around four years in training, Eren placing 5th in his class rank upon graduation.

Arc 1) Attack on wall Rose
Upon graduation, before Eren is able to formally apply for a position in the Scouting Legion, the Colossal Titan appeared the same as it did the day of the fall of wall Maria. Eren attempts to destroy it, but it vanishes in a puff of smoke after having broken the gate open.

In response to the crisis, the new recruits are scrambled and split into specific teams in charge of spreading to and defending different parts of the city. Eren is grouped with Armin. Upon seeing his comrade(s) killed, Eren leaps into battle after a Titan, only to have his leg bitten off below the knee, incapacitating him. The rest of his group attacks and dies as a result. Just as Armin is about to get eaten, Eren manages to pull his friend out of the bearded Titan's mouth, effectively switching places with him. Eren is swallowed, his left arm being severed as the titan shut its mouth.

It is later revealed that in the stomach of the bearded Titan Eren’s desperation and drive to exterminate all Titans triggered his first transformation into a Titan, bursting form the bearded Titan and proceeding to wreak havoc on all the Titans he could get his hands on. In the process he unawaredly saves the mourning Misaka’s life and is baited by a team of his classmates to help fend off a percussion of Titans from a storage headquarters for the compressed gas used to power their 3D movement gear.

As the Titans seem to overwhelm him and Misaka’s group is about to intervene, a certain Titan that killed one of Eren’s team members appears and Eren’s rage powers him to throw off the percussion and destroy the Titan. As soon as the massacre is over, Eren falls to the ground and his human form emerges from the back of his Titain form’s neck (with both lost limbs back) to the shock of all the onlookers. He is retrieved by an overwhelmed Misaka.

Upon his awakening, Eren seems to only have a faint dream-like memory of his time as a Titan and finds himself cornered by the military with only Misaka and Armin as his support. The military intends to kill Eren, thinking him an enemy. A cannon is fired at the three of them and Eren grabs onto his two friends and bites his own hand, wounding himself and partially transforming into a Titan, blocking the cannon ball before emerging form the skeleton. Eren allows Armin to try and talk them out of their tight spot with limited success until Commander Pixis intervenes.

A plan is made for Eren to use his Titan form to moves a huge bolder they had planned to use to stopper the gate if such and attack as this occurred, but were unable to move. Eren is assigned to a team including Misaka to defend him while he carries the boulder. Upon his transformation to execute the plan, though, he attacks Misaka, who tries to communicate with him to snap out of it, unsuccessfully. Eren ends up wounding himself and his body fails to regenerate, the mission is declared a failure. Despite this, the leader of the group, with some non-verbal convincing by Misaka, decides they must stay and guard Eren.

Armin arrives on the scene and convinces Misaka to go help fend off the Titans while he tries to get through to Eren. Eventually he is able to do so, and Eren moves the stone and is able to stopper the hole in the wall at the sacrifice of the rest of the team members (with the exception of Armin and Misaka). They are saved from the desperate situation after Eren’s transformation back to human by Rivaille.

Arc 2) Scouting Legion outside the wall
Eren again wakes up this time in a dungeon prison cell chained. Rivaille is there and upon hearing his motive to kill Titans says he’ll accept him on the team. Eren is left there for a time before he is escorted by Scouting Legion members to the court room where he is tried with one side calling for his decision and execution and the opposing side, the Scouting Legion, arguing to use his power to their advantage in scouting missions. After and outburst by Eren, Rivaille beats him accreting his dominance over Eren’s threat and it is decided his fate will be decided after a “test” mission with the Scouting Legion.

Eren, along with some of his old classmates that also joined the Scouting Legion, train for a month, learning long distance communication formation, before they depart outside wall Rose to the ruin in the region once protected by wall Maria. Eren along with most of the group are not told the goal of the operation but are simply expected to follow orders. Eventually, a deviant “intelligent” titan known as the “Female Titan” catches up with the Eren’s team and pursues them into a huge forest. Upon it’s closer approach and the death of some comrades from behind as Eren and his team simply keep running, Eren is tempted to use his Titan power and save his comrades and fight the Female Titan. Rivaille allows this choice, but Eren eventually decides to trust in his team, scarifying the last remaining member of the rear guard.

The Female Titan, suspected to be the same as Eren and mearly a “human in titan skin,” nearly captures Eren before being ambushed and captured herself. Eren and the rest of his team excluding Rivaille ride out of the forest firm in the belief that the titan was captured and her human self apprehended. This is proved false as the unidentifiable human form of the Female Titan kills one of the team members before re-transforming into a titan. The remaing three team members tell Eren to go on while they kill the Female Titan. Eren wishes to stay and fight with them, but again, is convinced otherwise and retreats. The three are promptly slaughtered and a regretful Eren transforms into a Titan and engages the Female Titan.

He ultimately loses the fight and his human self is captured by the Female Titan. Mikasa arrives on the scene in time to observe this and pursues to retrieve him, closely followed by Rivaille. The two team up to retrieve Eren, leaving the Female Titan alive and depart back to wall Rose, the mission failed and many soldiers lost. In Chapter 31, Eren is shocked when Annie smiled the same way the Female Titan did when she unhooded Armin. In Chapter 32, he's in shock when he learned that she is the Female Titan. When he tried to go into tian form by injuring himseld, he couldn't do it because of his shock and his mind was clouded. Going back to a meeting room, Eren apologizes to Rivaille for disobeying orders to fight off the Female Titan. If he hadn't done so, they wouldn't gotten in the predicament they're in. When Mikasa and Armin prepare themselves to take on Annie by themselves, Eren eventually overcame his shock and transformed into his titan form.

Natural strength
Eren is a strong human, and is even known as the person that he is the best at hand to hand combat in his graduating class, other than Mikasa.

3D manuver gear
At first, it is shown that Eren is not very skilled with the gear, and that he doesn't have any talent with it, but through sheer determination he was able to learn it and be in the top 5 of his graduating class. He isn't shown using it that much, but was able to hold his own with the Collasal titan, even for a while, until the titan disappeared.

Titan Shifting
After being swallowed by a titan, Eren was able to turn into a titan. He is much stronger than the average titan, and is able to beat down a whole group of titans quickly. In this form, he is a 15m titan, with shoulder-length black hair, pointy ears, and a huge mouth. Because of his intelligence, something regular titans don't have, he is able to out maneuver the others and quickly beat them down.

Relationships

 * Mikasa – Adoptive sister
 * Armin – One of Eren's closest friends