I'm pretty sure he's mention that in a conversation with Elk, but I could just be thinking of a different manga.
He was put into the world and his mom (to save him) reverted him back to a fetus and then gave birth to him. It doesn't explain it a whole lot but I think he is an incubus, at least to some extent.
He explained to Elk that he thinks he's a human.
But when reverting a toddler into a fetus again is changing his form on his body, she shares the blood and reconstructed a new body that is capable of using magic. So yeah he's a half incubus.
I agree. I think I remember his mom apologizing for him being an incubus....
If Minato's mom is a succubus then does that make Minato an incubus? Or at least half incubus?
I'm sensing the start of a harem....