Here is some links I hope you find useful:
He is mentioned in many texts. In solomonic texts he is tied to the big dipper. He is known for many things, lust, finding things, hiding from others, said.to run casinos in hell and more. In the royalty of hell he is said to be a prince and have 72 legions under him. There is a lot honestly but you need to be willing to really read.
If it is truly your guardian angel, then they will only lie to you if it is for your own good. They would never lie just to see you fail. The point of a guardian angel is to guide you on your spiritiual path and help you make good decisions in that. But by all means, if you are wary, consult more than one source. Your guardian angel will never fault you for having good sense.