Eren Jager is the main character from the Japanese anime series “Shingeki No Kyojin/Attack On Titan”. An interesting protagonist living in a world of fear and epic despair, Eren Jager is the son of Dr. Jager, a man who belongs to a powerful group of men who hate humans and wish to destroy them. 100 years ago, the head of this group- a Japanese doctor, created a mutagen which would turn humans into gigantic, mindless killers. He released this mutagen into the water system, causing the nearby humans who relied on it to mutate and become 6-20 meter giant zombie-like killers. These giants, called “Titans”, completely genocided the entire Asian and African race and nearly killed the Caucasian race as well. To prevent himself from getting killed by the Titans he created, the Japanese doctor injected himself with a mutagen that allowed him to transform into a Titan many times stronger than an average Titan at will. He also gave this mutagen to a selected group of trusted followers-creating a race of Titan shifters.
Dr. Jager is a Titan Shifter. His son, Eren, is not. 100 years into the future, Dr. Jager and the rest of the Titan Shifters are planning to attack the surviving humans who have breached themselves behind giant, fortified walls reaching 60-150 meters tall. Dr. Jager is a spy against humanity behind the walls. Before Jager leaves the walls for the assault, he gives his son the Titan Shifter mutagen. The other Titan Shifters-who are the only ones strong enough to breach the walls, break down the outermost wall, allowing many Titans to swarm inside, killing many humans. Eren escapes with his life to a second wall, which is breached a couple years later by Titan Shifters. When the Titans are slaughtering human soldiers-of whom Eren is one, he discovers he is a Titan Shifter.