Charles Helliwell's Answer:
This is indeed an extraordinary set of events that you describe. Was anyone running this department before you were appointed, or was the Dean solely responsible ? I suspect it was the latter, and this being the case, there is nowhere for you to go than straight to the top - to the Chancellor of the University. You have no other option.
However, before you do so, you must first accumulate sufficient evidence of the Dean's behaviour and inappropriate conduct, to present your case. Heresay and innuendo count for nothing. You have to hand write the conversations you have with the Dean in a paper notebook, which must be your property and then date and time each conversation you have, no matter how trite or inconsequential.
In addition, you must try and restrict your conversations with the Dean to a minimum and keep your interactions with him on a strictly 'in writing' basis.
This is going to be tedious, time consuming, laborious and unpleasant, however, this is the only way that you are going to be able to protect yourself in the short-term and retain your sanity and integrity.
Sadly for you, there is no future for you in trying to engage with the Dean. From your description, it appears to be beyond recovery. He seems to be completely out-of-control and intoxicated with the power he chooses to wield over those who work for him. That he favours two other female members of staff seems to suggest something even more sinister and incriminating. So, you will have to deal with him, as you have to deal with all those who bully, harass and intimidate others, by providing evidence of their actions.
The VP may well be an innocent party in all of this, but because of the positive impression that the Dean gives the VP, it is not worth the risk in talking to him or taking your evidence to him.
Just remember that once you 'blow the whistle' on the Dean, you are exposed and vulnerable, so you might as well blow the whistle to the highest authority available; and that's the Chancellor. The Chancellor has to be told, because what you have to report is potentially a threat to the reputation and integrity of the University.
Be prepared for the unpleasantness which will undoubtedly follow, because no one is going to thank you for it, and last but by no means least, please make sure that you have another post lined up to go to, because it is unlikely that you will be asked to remain in situ.
Having said that, employment law in some countries protects 'whistleblowers', so you may find that you are protected; whilst in other countries, public sector workers are protected by their union, so that too, is a possible route for you to pursue.
However, in the end, Nathan, you will realise that the working world is filled with people like the Dean, and that you will probably encounter a similar personality at some future point in your working career. So it's always best to learn how to deal with them sooner than later. Yes, you could just walk away and leave someone else to sort it out, but you don't strike me as that sort of person.