I wrote a post about spoiled priests (and nuns) about six years ago:
My impression is that few people have done so much damage as spoiled priests - who brought 'inside knowledge' of what they attacked.
Many were talented, learned, charming, eloquent, energetic, excellent writers - which of course only made them vastly more dangerous when they crossed over to serve the dark side.
If we add to them the numerous less famous priests, pastors, monks, friars (especially them!), bishops, archbishops and a Pope who were to a significant and crucial degree covert apostates (mostly in the sense of re-writing traditional Christianity to suit modern sensibilities) - then it can be seen that these foes masquerading as allies, these wolves in lambs' clothing, constitute just about the most important servants of evil outside of Communism (from which they were, of course, not distinct).
Check out the whole thing, including comments - and see if you can suggest further examples of the type - think of this as doing a public service for this blog's readership.