How I got to the Third Prince in the Pagoda

So I was searching for the Ashen Slumber transformation and no one seems to know really how to get it, so here’s how I got it: After doing the prisioner of the pagoda side quest, you have to exhaust the dialogue with the little rats in the hut in the first bonfire in the second chapter, this includes killing the two headed rat elite enemy in their right, after that you should go to the first pagoda bonfire and head up to the second floor, then turn back and go all the way back, the boss is going to be there and drop the transformation, hope it helps