Our creators gave us just enough mental ability to survive on the Earth, no more. Our brain is too primitive to understand the question of where THEY came from and to ask such a question validates the presupposition.

Even the Greys that pilot surveillance craft, have a limited brain I suspect, albeit, more advanced than ours. Remember that our alien creators are extremely efficient and wouldn't give us more than we need.

You should learn to avoid questions that have no concrete answer that we can comprehend (eg; what is the purpose of the Universe?). Pondering such things only wastes your life and to be honest, fear is what drives such questioning.