'Who Created God?' Is an Illegitimate and Impossible Question Based Upon Confusion Between Categories
The question:
"If God is the creator, then who created the creator?" is illegitimate because by definition, the Creator is uncreated.
He is eternal, without beginning, without end and all affairs return back to Him:
(وَأَنَّ إِلَىٰ رَبِّكَ ٱلْمُنتَهَىٰ)
"And that to your Lord is the return (of all beings and affairs) (and of all perfections in attributes)." (53:42).
Thus to ask who or what created something that is uncreated is the way of:
a) an ignorant person devoid of intellect,
b) a lying deceiver, a sophist.