Eren Jaeger is a main protagonist of the anime "Attack on Titan". Eren and his childhood firend - Mikasa Ackerman - horribly witnessed the death of Eren's mother at the hands of a Titan. This is the root of Eren's hatred of the Titans.
Eren's father is a mysterious man that has possibly given Eren a very unusual power.
Eren eventually becomes a member of the Survey Corps. and is reasonably skilled with the Maneuver Gear. It's apparent that Eren is a link to the secret behind the Titans.