[Donghua] Question about losing control

!I assume that potions take the powers from mythical creatures and imbue them into humans and losing control is reverting to the original creature. That being said, what's the deal with Old Neil? When he loses control he is fully capable of speech and thought. Sure, when that Mandated punisher guy lost control he seemed to recognize Old Neil, but he couldn't talk. Is it because of Old Neils Do as you will but do no harm mantra? do ideas and thoughts of those that lose control affect the transformation? since Old Neil retained his Consciousness does that mean that some who lose control can be saved? And if my earlier assumption is correct, wtf kinda monster is his potion based on.!<