"The Earth was corrupt before God, and the Earth was filled with violence."
Book of Genesis 6:11
Corruptor does not see much play but I believe it truly has a lot of things going for him!
Corruptor says Beast are Monster, Mortals are Undead and Angels are Demons. Essentially he turns everything Evil in your deck (and everywhere for that matter) as long as you play Beasts, Mortals and Angels. While turning Angels into Demons isn't that interesting, as I found there are not a whole lot of synergies with it, it is quite different for Beasts and Mortals.
First of all, Corruptor adds types, he does not replace them. It means that Beasts are Beasts AND Monsters. Same for Mortals who are Mortals AND Undead.
The first "big" combo of the deck is playing to draw cards, sacrifice it in a fight or to , or to for ramp and then bringing it back to life with . brings it back as well to draw even more cards.
This Avatar also lets you play your Evil Minions very quickly since it has 8 Sites to reduce the costs of Minions : and . And since Beasts are Beast AND Evil, both of them works with your Beasts and are interchangeable. Making a Monstruous Lion or Gyre Hippogriffs a turn earlier works well and is reliable with 8 sites that can do it. Also, you ignore thresholds with these sites so 
on the Hippogriffs is not really a problem in a predominantly 
deck.
is also a great Minion with : you don't need the expensive threshold since it's an Evil Minion with Corruptor and, same with Grandmaster Wizard, you can Carrionette it and/or bring it back with Lady of the Lake as well. falls in the same category, you can banish pretty much anything to bring it back from the cemetery. And you do resolve Genesis abilities with it! (so if you banish, say a Grandmaster Wizard with him, you draw more cards!) He is also a prime candidate for since you can bring him back easily from the cemetery. In the same vein, draws you many cards.
Quite fittingly, the deck struggles to put this whole strategy of drawing more card in action when is in play. If you know you opponent plays it, I would strongly suggest holding Atlantean Fate to deal with it.
Go forth with your Monsters and bring back your evil Mortals to life to never run out of spells!