I thought the odds were 1/8? Oh well, 1/16 does appear to make more sense.
Yeah I'm killing him in his original form; he falls quick to a ninja with focus and 2 air knives. Up to 9 now total, will probably only get 3 a day. With death sickles I could easily get 10 or more per day :(
Finally got 99 light staffs. There are 1894 Metamorph corpses in that room with the 5 chests. Amazingly got the 2 ash from the crystal guardians on my first try. Any more is just ridiculous; My calculator doesn't even give me a fraction for (1/16/)^4 or even (1/16)^3.