Where did the nickname America's Monster come from?
I haven't seen it specified anywhere regarding how he got this nickname other then his peers giving him the name. Not to mention I don't think I've once ever actually seen any of the team explicitly call him America's Monster or mention it unless I missed that bit somewhere.
I think with his manipulation skills and his overall ruthlessness on the field it may warrant the nickname with his reputation but I wonder where it actually originated from. What was it explicitly that he did to earn the title?
I have a couple of theories on how he got the nickname
I think it could have from something to do with Perseus most likely back in the 1960s when he was in Vietnam hunting him down the first time. It's obvious Adler has a hatred for Perseus and most likely as he continued hunting him down in Vietnam I'd imagine he'd get more and more annoyed that Perseus kept evading him that he'd start to resort to more violent and extreme measures to get the information and intel he needed to stop him. But other people saw it and thought he was getting pretty gruesome just to find the guy and gave him the nickname perhaps?
Another theory is with his work on Separation in the 70s. The drug causes induced schizophrenia for any of the subjects and just like with Bell and MK-Ultra, Adler manipulated their memories to get what he wanted no matter how painful or traumatic the whole experience was for Bell or the other subject exposed to this. But for Adler he was doing a job, and he most likely didn't care enough about the suffering he was causing in the process causing others to label him as America's Monster.
Either way the title most likely came from something brutal he did, he didn't just earn the title for nothing. But I feel like either his work in Vietnam or Separation could have contributed or possibly earned him the nickname.
I did have another theory but I'm not sure on it tbh I thought maybe after he got his scar some people could look at him as though he looks like some kind of monster and give him the nickname but I'm not too sure about that one.
Even then, as I mentioned, I've never heard anyone explicitly call Adler by that title to his face or others. Maybe he dislikes the nickname because of whatever memory or thing he did its accociated with it. Although, at the same time, given his reputation that he doesn't seem to hide, I can't see him being opposed or guilty about whatever he did to earn that title. I could probably see some of the other guys at the CIA using it to scare the rookies, specifically Woods, maybe.