Consequently you are exposed for what you are.
You are asking for proof of an intangible. Clearly in that case, you win - For those that hold faith however, it is widely accepted demons inhabit some men. As there are Preists and pastors in God, there are others in Satan, invoking its name and affording it a vehicle to perform evil. From the arena of my denomination, the laying of hands is a holy work of the spirit. Is the holy spirit tangible - plainly no. Is it non existent - clearly not. If we cant progress past this premise we have little to speak of.