That is a so-called "Complex Question."
A complex question, trick question, multiple question or plurium interrogationum (Latin, "of many questions") is a question that has a presupposition that is complex. The presupposition is a proposition that is presumed to be acceptable to the respondent when the question is asked. The respondent becomes committed to this proposition when he gives any direct answer. The presupposition is called "complex" because it is a conjunctive proposition, a disjunctive proposition, or a conditional proposition. It could also be another type of proposition that contains some logical connective in a way that makes it have several parts that are component propositions.
-Wikipedia
But you should first define your terms.
1. Define "angel." (I.e., what is your definition of "angel?")
2. Define "slave." (I.e., what is your definition of "slave?")
Then and only then, you can attempt to definitively establish whether angels even exist or not.
Only then is it worthwhile to attempt determine the answer(s) to your question.
Regards,
Are you happy now?
1. Angels are pure spirits without a body, created to adore and enjoy God in heaven.
2. No. A slave is a person who is the legal property of another and is forced to obey him.