Kindler - I considered that, but then that would also defeat the significance of what Bob knows. Not to mention when he discussed how Immortals could be killed, he said it didn't matter if Harry chopped up the Winter Lady and burned her ashes unless it was on Halloween because she would reform otherwise. When Harry questions how he was able to kill Aurora, it is explained that it was because it was in a specific killing ground for immortals (Chicago-over-Chicago), created by the Queens. And Harry killed her without killing the mantle. In fact, I think Mantles can't be killed per se, but transferred or changed. Which is what happened to Maeve and Aurora. But mantles don't apply to Outsiders I think anyway. As mantles seem to be shaped by mortal imagination.
I think HWWBf is able to come in, just not all of him. But it doesn't really matter, he has the same Outsider limits as He Who Walks Behind. As for the summoner, probably another Black Council flunky.
Griff - see above. Nowhere has it been said mantles can be destroyed. In fact, the Mothers specifically tell Harry that cannot be done - energy cannot be created or destroyed. It can be hoarded (like Dragons do) or rendered valueless or sold (both of which are change). I believe that passage is in Summer Knight when Harry is trying to find out from them what could have happened to the mantle of the Summer Knight.
