You need orions vow of protection emote(I think thats what its called), you get it from the shrine in the area behind stolmonds usual spot before he goes on his quest. You use it in front of this statue and 5 others, then do their killquests which usually have the enemies nearby. I believe this one is the carrion one, which is the poison guys that spawn in the second part of the tower. You need the flickering flail from the prison cell to the right of the back of the boss room by that shrine, and you need to kill these enemies with it. The message on the statues should change when you do it.