The way it seems to be phrased in episode 5, Battler thinks that there is no such thing as magic whatsoever - not just that the Rokkenjima murders are completely natural. I can almost accept this, even in conjunction with Beatrice's appearance, the spontaneous dismemberment of the other family members in the afterlife, and Beatrice's conversations with Frederika - if we accept that we are in the afterlife/metaverse where such things CAN happen, and that Battler only believes magic doesn't exist in the real world, otherwise the whole thing falls apart in my eyes.
But how does Battler managing to prove that the Rokkenjima murders were natural disprove the existence of magic? That's really dodgy, almost inductive, reasoning - one counter-example doesn't disprove the whole hypothesis. And what of the golden butterflies?
If I've misunderstood completely and Battler is happy to accept the possibility of supernatural forces as long as they didn't cause the murders that's fine. But as it is it makes my head hurt
