He is the most impulsive and brutal of the three, killing his enemies mercilessly and even laughing crazily when he kills many people. His triggering word is "mother."
What Auel vividly remembers is that his mother was a researcher at the Alliance lab in Lodonia. He was chosen to be subjected to the brutal training program to produce hard supersoldiers to fight against Coordinators. Together with his comrades he sneaks into the PLANT colony Armory One, where he steals one of the three new Gundam-type mobile suits, the ZGMF-X31S Abyss. He then uses the heavily armed suit to wrack havoc inside the colony, killing many ZAFT soldiers. After that he is involved in two other battles in space (the first in the debris belt, the second on the remnants of the destroyed PLANT colony Junius 7) and after the start of the Second Bloody Valentine War, Auel and the rest of the Phantom Pain go to Earth. There they are again involved in several battles against the ZAFT ship Minerva, however with no great success. Auel however is able to sink one Vosgulov-class submarine which accompanied the Minerva. Auel and his two comrades later investigate the ZAFT-controlled city Diokia, where the three for the first time meet Shinn Asuka and Athrun Zala, however none of them knew who the other is. Later when ZAFT discovers the laboratory in Lodonia and Auel finds out about it, he freaks out, because his mother was stationed there. In the confusion, Auel says his trigger word "mother" and collapses into tears. However he quickly gets help from the doctors on board the ship. He then again fights against the Minerva at the Dardanelles, where the Abyss is damaged by the ZGMF-X10A Freedom, however it is quickly repaired. Shortly after Stella was taken into the care of the Minerva, Auel and Sting had all of their memories of her erased. The latter recalled nothing, but Auel felt that something was missing, suggesting his amnesia was not complete. During the Battle of Crete the Abyss is destroyed by Shinn Asuka when he uses the beam javelin of his ZGMF-X56S/γ Blast Impulse to stab directly into the abdomen of Auel's suit, which causes the suit to explode under water, killing Auel in the process.
Auel most of the time treated Stella with either some sort of contempt or as a weapon, mostly like Sting, but unlike Sting, after their memories were erased, Auel still had a feeling in the back of his mind that something was missing, such as before his final battle, he noticed that Stella's mobile suit was missing, though he didn't know exactly what he was thinking of at the time, suggesting possibly a fondness for her.