Magic Forums

Ok let give this a try, I have vaguely skimmed over Angels and Demons never taken an interest, but as Demons are always mentions I kinda know what there are and what there about, from many different views, but Angels not a clue, I joined the public chat as fallen angel, dark angel and arch angel where mentioned to me the all portray a angel that is know longer on a righteous path but apparently there is differences. Could anyone give me a link to a good source or clear this is up for me please.