Hmm... I don't think Meredith wants to kill Kielnode. The one that tortures Kielnode is that old hag, and the one that impale Kielnode on the wall might be them renegade demon.
They know that would open Roods eye towards the human, shaken him off so that Demon King Persona would appear
I know It was lispen who chained up Kiel. But even if Meredith didn't order to torture Kiel, didn't he know about the torture?!