Read this: Additionally, there are a number of Assistant Chiefs of Defence Staff, including the Assistant Chief of the Defence Staff (Reserves and Cadets) and the Defence Services Secretary in the Royal Household of the Sovereign of the United Kingdom, who is also the Assistant Chief of Defence Staff (Personnel).
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What assistant in the royal household is also responsible for Reserves and Cadets?
unanswerable