Reiner Braun

Reiner is a graduate of the 104th Trainees Squad and graduated in the top ten of his class. He was assigned to the front guard after the second attack of the Colossal Titan

History
Like many, not much is know about Reiner's early life. He graduated in the top ten of his trainee class, coming in at second, just under Mikasa Ackerman. As part of the defensive effort of the military after the second attack of the Colossal Titan, he eventually found himself with the front guard. However, with the supply team stuck in the headquarters, he was essentailly immobilized with many of his teammates on a rooftop. Joining Jean's group in the rush to the HQ, he was among the survivors. With the subsequent arrival of Armin and Mikasa, by way of rogue titan, he helped to clear and secure the supply room.

Initially sceptical, Reiner suggested they help the rogue titan when it was being overwhelmed by a group. However, it turned out not to be necessary when it broke free at the sight of the titan that killed Tomas. He was among the first people to know about Eren's titan form, when he emerged from the giants body.