The most common and most likely answer to this crossword clue is the 6 letter word AZRAEL
I've seen this crossword clue in Independent
A
Z
R
A
E
L
Buddy explains!
The straight part
We know that "not one keeping body and soul together (i.e. the Angel of Death!)" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not one keeping body and soul together (i.e. the angel of death!) = azrael.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.