During his childhood, Aaron heard his grandfather's stories about the Golem, Thules, the Judah Initiative and such, however he simply believed they were made up to help him cope with what he did during the war. His parents did all they could to spare him from everything his grandfather had to offer him. When he was thirteen, his grandfather gave him an instruction manual on Golems, as he would inherit everything, but during school he lost his way, and used the pages as cigarettes.
After his grandfather was murdered, he inherited the Golem, and was left with problems, particularly as he had no idea how to claim the Golem, and the Golem disliked his casual disinterest in his faith, along with Aaron's ineptitude as rabbi and therefore as the Golem's master. Following Sam and Dean's arrival he followed Dean, while the Golem followed Sam. He later saved Sam from the Golem, after the two entered a skirmish.
Back at his place he explained what he knew to the hunters, who filled him in on the rest, and then went with them to recover the book his grandfather had found. He was shot by Torvald with a poisonous dart, but was saved by the Golem and Dean. After which he was still unsure what to do, but disagreed with their plans to stop the Golem, as he felt it was his responsibility.
Suddenly other members of the Thule Society broke in, and Eckhart managed to incapacitate his Golem, mocking him as to how he never possessed him, as he didn't know how. The Thules caught them and it seemed lost. However at the last minute he came to, and smashed a wooden board over Eckhart, Sam and Dean killed the remaining members, save one who escaped. In the end he finally took possession of the Golem, realizing that the Thule was still out there, and that he was now a Judah member.
Sam and Dean later call Aaron about the Thule when they suspect the society of being behind two murders. Aaron tells them that he has dropped out of college to hunt the Thule and in the three and a half years since they met, he and the Golem have hunted down half of the Thule members in the ledger with Aaron killing six and the Golem the rest. Aaron tells them that the Thule have mostly stayed in Germany but the Thule High Command is planning something big that will have them all in one place at the same time. All that Aaron knows is that the documents he has been able to get call it "Das Blut" or "The Blood."
As a child, Aaron enjoyed his grandfather's stories about the Judah Initiative, World War II and the Thules, but only saw them as interesting stories. He cared a lot about his grandfather but during high school, "drifted" to the point that he used the pages of the Golem instruction manual his grandfather had given him for his Bar Mitzvah to create joints. Aaron is also indicated to have been a slacker growing up, telling the Winchesters that he cheated his way through Hebrew school, resulting in him not having a good grasp of the Hebrew language. He also doesn't observe many Jewish traditions as pointed out by the Golem.
When first encountered, Aaron was timid and considered the Winchesters psychopaths when he witnessed them burning Torvald's body, seeming to be scared by the sight. He also had no real interest in controlling the Golem and was highly annoyed to have ownership of it. However, he was also reluctant when faced with the idea of giving the Golem up because his grandfather had entrusted it to him. As time went on and Aaron learned more and more of his grandfather's work and the Thule, Aaron grew more and more interested in continuing the task he had been left. Aaron also started to show more courage, attacking Eckhart to give the Winchesters the chance to fight back. However, Aaron couldn't bring himself to use a shotgun to actually kill someone and instead attacked with a broken table leg.
Following the fight with Eckhart and the Thule, Aaron accepted his role as a Judah Initiative member and the controller of the Golem, seeing it as his duty to finish what his grandfather started. After accepting his role, Aaron went as far as to drop out of college despite knowing his mother wouldn't like it to hunt the Thules and became enough of a warrior that he was personally able to kill six Thule and together with the Golem, kill half of the known Thule membership. As a Judah member, Aaron came to be considered a threat even by Commandant Nauhaus, the Thule leader.
Powers and Abilities
- Golem Control - As the only surviving member of the Judah Initiative, Aaron possesses the ability to control the Golem to do his bidding.
- Hunting Skills - While initially not possessing any skills whatsoever in hunting, over the course of three and a half years Aaron gained enough hunting skills to track down and kill half of the Thule membership, killing six Thule personally.
- Surveillance Skills - Aaron has displayed an impressive skill in surveillance, even before he started fighting the Thule. When detected following Dean Winchester, Aaron was able to successfully trick him into believing Aaron was not following him despite Dean's years of hunting experience.
- At the end of Everybody Hates Hitler, Aaron states "looks like I'm the Judah Initiative now." In The One You've Been Waiting For, its confirmed that Aaron is now considered a Judah member as Commandant Nauhaus is annoyed that the Winchesters are hunting them as well as "the Judah and his revolting Golem."
- In Everybody Hates Hitler, Aaron tells the Winchesters that he cheated his way through Hebrew school.
- Aaron may be able to speak or at least read German as he read from the Ledger of the Thules without any apparent form of translation in front of him, unlike Sam. In contrast, Aaron doesn't have a good grasp of Hebrew due to cheating his way through Hebrew school rather than paying actual attention.