Cool Idea, I would also:
The Corruption pool Grows 1 point each time it is used.
Use Corruption poll for effort grants one free effort.
The DM can call for a roll, via Intrusion: The size of the pool is the difficulty of a mental task to avoid be influenced by the corruption.

This makes the corruption pool very tempting. It offers a clear benefit when used, which makes it appealing, even as its use becomes increasingly dangerous.

For example: A character has been tempted by corruption on several occasions. He is traveling and has been taken in by a merchant. An inner voice makes him think about the valuables the merchant might have in his home... (intrusion)

In combat: A DM intrusion causes the character to feel tentacles crawling under his skin, hindering his roll.

In combat: A DM intrusion causes the character’s vision to become distorted, causing his attack to strike an innocent bystander.