One thing i found and is probably completely unrelated to the pendant was the door to the Kiln of the First Flame is not the only door that looked the was it did. There is another door in game that is identical to the one you use to access the kiln.
The second door is located in the room where you fight the demon centipede boss (which seems to be quite large for no reason). It is a large stone door cracked down the middle just like the one that access the kiln.
Has anyone else noticed this and tried anyways of opening the door.