As long as Darth Tyranus is in any arena, each Quarren unit gets Fury 4.
As long as you have another Separatist unit in the Ground arena, Quarren Isolation League can't be attacked.
Keywords
Fury
Fury X: A cumulative ability triggered by the initial dice roll that means, "When you roll at least one natural four with this unit's attack dice before re-roll, roll X additional attack dice." Only the first natural "4" counts. A four rolled after re-roll doesn't matter. If your unit gets the Fury ability after you roll attack dice, it's too late to roll additional attack dice. Fury applies only to dice rolled for an attack, not to dice rolls for abilities like Retaliate. Accuracy can't increase the die roll to a natural "4."