Are guardian angels real? If so can you contact one, and who regulated them? (besides God) If not how did the Idea of guardian angels come about?
Eh, guardian spirit is more appropriate. I mean, there are a lot of Gods, and a lot of entities. If someone protect you, its somewhere in the universe some entitiy takes care of you for a reason you have to figure out.
If putting my own thoughts on it from experience, yes they are, yes you can but it's tricky, and for the rest >>17215358
>17215358 this guy nailed it, and they may guard at their own will or by being commanded to.
Not exactly how it works and wouldn't be to the same degree, especially power wise, though there are other ways to get familiars/spirit guides if that's what you're after.
There were already quite few guides posted on /x/ so you can go through archives, than again, some of them are crap so first do some research on the ones you find as you may be inviting more negative beings than anything.
Rufus Opus modern angelic grimoire
Learn how to communicate with entities. And with that I don't only mean to percieve them, but also learn the way one should word his requests without accidently pissing people off