FWW is physical damage.I usually go with Frenzied Whirl Wind, AP and Runic Corruption. Frenzied is chaos damage, so takes advantage of the corruption. Does good damage at 120 ninjitsu, and makes the pet viable for 1 v1 or groups of mobs. Plus, as stated above, it puts more abilities in the rotation. one problem with fire beetles is the native 500 mana. Don't need it with 2 abilities. But with those 3, and the 500 int, you will find you dont run out of mana often even in long battles.