My illusion is 33. I was wondering if I dual cast fury, what could I effect?

I think if you have no other perks, such as Rage, Animage and Kindred Mage, then Fury dual cast will affect something around Level 13 or 14, as it slightly more than doubles the power of the illusion spell. If you invest in Dual Casting, Rage, Animage and Kindred Mage, you can affect anything up to Level 80 with a spell called Frenzy, which is basically everything besides The Ebony Warrior.

Thanks.