This unit cannot be corrupted.
Does his constant effect prevents it from entering play corrupted via Warpstone Excavation/Pleasure Cults? According to FAQ units that enter play corrupted don't change their states:
Q: If I control Fellblade (CC 100) and my opponent plays a unit into a zone containing a Warpstone Excavation (CS 116), is the unit considered to have been corrupted, allowing me to put a resource token on Fellblade?
A: No. A unit that enters play in a particular state is not considered to have changed states. So in this case there is nothing being corrupted to trigger Fellblade. However, if a unit already in play moves to the zone that contains Warpstone Excavation, then it is considered to have been corrupted and a resource token would be placed on Fellblade.