[@Kangutso], my thoughts is to make sure that the ash which was taken from ruin and death stays a symbol of ruin and death, somehow. I picture a reaper-like figure, although with some weapon other than a scythe. Being made from ash makes me picture Ashlings, so by accidental irony I picture an avatar thematically similar to ashings. Since it is made from ash, I also envisage shapeshifting powers, as well as being able to fly about as a cloud of ash.

Although it also depends what you want out of it.