wingsandsword
Legend
BUT your Cleric's magical powers are based on the will of a deity. It is not innate, and can be revolved by the will of the deities and the whims of fate since he is but a lowly mortal playing with forces that he doesn't understand without the intercession of the holy. His powers can fail. He knows this, since he may have seen the powers of other clerics fail them if theirdeity or the NPC's deity deems him/her worthy enough to enter the afterlife unabated or if they decided that the NPC doesn't deserve to be healed or remain in the realms of the living for one of countless reasons.
Like it or not, when you try to use magic and powers as a justification of why you can do X, you need to remember that their are larger forces outside of your character's control who can put an end to their desires.... That is unless they want to wage war against the deities and Ascend to Godhood.
That depends entirely on the flavor of the setting, and between different editions of D&D these assumptions were even written into the rules.
In AD&D 1e and 2e, 1st and 2nd level Cleric spells came from internal faith and training and would work even if the patron deity was dead, 3rd and 4th level spells were granted by various intermediaries (what we now would call Outsiders), and 5th level and up were granted directly by deities. Of official settings, I think only Dragonlance challenged this, with Clerics losing all spells once the Gods of Krynn left. Even then, once the spells were granted at rememorization, the were the Clerics to do with as they chose, the deity couldn't just veto each casting, but they could cut the Cleric off from more spells when they would otherwise rememorize.
In 3.x, Clerics could be clerics of a philosophy or ideology, and thus could be unaccountable to a specific deity.
Yes, it's whatever the DM wants, but the assumptions written into the background material have left lots of loopholes and contradictions to the the idea that a deity can just instantly refuse to have a Cleric's spells work if they don't like what they are doing.