I was exploring the mines outside of the dorgeshuun city, where the agility course is. (That's the southern end of the city up the large staircase. You will also need a grapling hook to get to the plateau they stand on.) And I found these two talking to eachother: What I strongly suspect is that this great "power" is actually tears of Guthix. Either that or the goblin's lava power generator. Now if these Zarosians got ahold of either... Also, pickpocketing the mage gives you an amulet of lucien, which opens up one more dialogue option when speaking to them. You can find out that they were sent by Lucien. Using the ring of charos (u), I was able to crack this much more out of them: Also, here is where they are located in the agiltiy course: What's next?