Aristo, in accordance with Listener editors’s guidelines, subtractive anagrams are generally of the form:
( A* - B*)* = C
“A” is the main “ fodder”, but often the elements of “B” are letters randomly distributed in “ A”, hence must be shown as such by an anagram indicator. Similarly, to generate the definition “C”, the remainder needs to be reconstituted.
That’s why the final “ devastated” .
Tricky, but it does generally produce a nice surface - often quite a narrative - also lots of scope.
Hope we’re not teaching grandma(Pa) to suck eggs.
We do like short, pithy clues - but the scope is often reduced.