Eren takes the form of his enemies
Eren jaeger is the hero of the manga series and cartoons Attack On Titan. In this alternative world, creatures called titans have one day landed on Earth and started to attack entire cities by devouring their inhabitants, which is quite easy for them since they can measure up to 15 meters high. When he was a teenager, Eren saw his mother being devoured by a Titan and decided to join the army of one of the big fortified cities in order to fight them as best he could. Eren also has the power to control them and take their form.