system
A chat on 4chan
human
Why not quote an expert? 
>for many centuries
Parasites were here before Christ.
>OP here.
Please select a name, I suggest Para-OP. Namefaggotry doesn't have to define you.
gpt
The rundown I wrote is a connecting of the dots of all the viable information from the sources available in these Generals. Jerry is something of an expert, but only really in his own way, as it pertains to his line of work. That applies really to most of the sources and the information therein provided in the Generals. Given my ability to connect the dots, my own experiences, and the knowledge I posses of these beings (which coincides with the aforementioned “dot-connecting” and experiences), and given the knowledge I possess in general, some may say this sounds arrogant, but I think then I possess the capabilities and/or “knowhow” that suffices as the expertise you seemingly request.
As for my usage of the word “centuries”, I didn’t for intend for it to mean before, after or during the time of Jesus Christ, it was meant more generally. For what it’s worth it could be said that one of the best, earliest known accounts and/or descriptions of these beings is in the Gnostic texts, which was during Jesus’ time and came from a group that he was (apparently. I say apparently because while I think it’s undeniable he existed, and there’s undeniably much truth in certain parts of the Gnostic texts, it can be a bit hard to tell at times when Jesus actually did or said something given what has been made/happened to some of, if not any of the accounts of his life) involved with, so it could be argued then that some of the most vital information pertaining to these beings is of his time, but I digress.
As for the third and final point of your post, I have given myself the name “/par/-OP”, which I will use from here on out. Even when making these threads, which is perhaps already evident, but I felt somewhat compelled to mention it.