Got this as an ancestral rare. Am an arclash sorcerer. Does the enchantment work with fireball enchant or only if you cast it?
Why so angry? You sound like a Barbarian! 
Joke aside, I would say nope, because the enchantment is not a cast of fireball, I would think…
But you know what? It’s a good question. Test it now that you have the staff, and lest us know! 
I’m pretty sure it works, but honestly it’s weak. A good rare with a good affix is more damage than that unique. Pretty sad, but it’s true.
3 casts, 5 explosions. 5/3 increase. Good affix in a two hand will do better than that and the dmg is consistent.
Edit: My bad; I thought the staff as well.
I still cannot tell to be honest. I dont think it does but it would be great if a developer chimed in on this or someone who knows for sure.
Based on testing the staff gives no extra benefit to the fireball enchantment. But if enemies die due to the extra fireballs they will still explode for extra damage. Hope that answers your question.
Is that the one where it does 70% LESS damage?
Who on Earth came up with that number?
Except for Raiment sorc uniques are almost all garbage, with a couple being almost o.k., but still much worse than half-way decent yellows. Even Raiment falls off at higher NMDs when defense is needed. I average 4-6 unique drops a day and they all get sold. I don’t even to look at them anymore
Edit: Sorry, I thought you were talking about the unique staff, but you I guess you were not