The Hidden are those Angels who no longer believe that it is in the best interests of their human charges–or the Source’s original mission–to follow the “old ways”. They believe the concept of freedom of choice has been so eroded by the growing strength of the demons that they can no longer sit idly by and watch Earth be completely subsumed by the demonic agenda.
The problem is, the demonic agenda is always changing…
The Hidden most probably come from all angelic groupings and hierarchies. “Most probably” because the actual membership of the Hidden is unclear. It is possible that there are angels still ostensibly working towards the Loyalist agenda, who are actually double-agents for the Hidden.
The Hidden have created strongholds on Earth from where they plan their own agenda of revenge against the demons, how to influence key humans, and how to revolutionize heaven. Their hierarchical organisation remains secret.
As the name suggests they are for now hidden from the view of the Source and the Loyalists, but as their numbers increase maintaining cover gets more difficult.
The Hidden are most often human in from, and it is unclear how much of their original angelic powers are maintained once they leave the angelic realms and come to Earth. However, from the unwritten lore it is understood that they can still challenge a fully-fledged Loyalist when necessary.