Destroy The Fiend Altars

Archaeologist Samhein tells you, "Did you happen to see some fiend altars while exploring the area? I came across some evidence that suggested the presence of these insidious altars in the immediate area." "If these altars are indeed active and located near this outpost, they present a grave danger to the local residents. Should you destroy any that you find and bring me the fragments of, say, three of them, I will give you a hefty reward. The fragments would be very useful in discerning their nature."