I spent a hour and a half last night continuously running around in circles targeting and sicking my pet on all these faeries to get this Power of Earth.
I killed all that spawned except for Gearheart and the Princess "I heard you might get a bigger faction hit" also the Princess was kind enough to say I could hang around as long as I didn't nibble on their houses. So I didn't disrespect her like that, instead I just slaughtered her whole family for almost a couple hours. She finally despawned. After that a faerie guard finally dropped the Power of Earth, I wasn't intentionally trying to ruin my faction but in the end they are very forgiving. They stilled conned amiably to me, and funny thing is...
I unlocked the achievement FAERICIDE
Level 55 Mage