My theory for who are the real parents of shirone is that it's the kid of the headmaster. They couldn't give birth, and at the moment of her death because of the experience, her wife created a singularity with her wish to have a kid. That would explain why he looks like him, that would explain why he appeared from nothing, and him being a result of magic would explain why magic loves him so much and how he's able to have such great results/impossible feats. The downside would be "why would he have appeared so much later when the headmaster is old" and it's true that a bullsh*t reason like "uhUhuUHUh space and time does not count in a singularity~~" could be made but it's still interesting to see in wich point it wouldn't work.
Would love to see other opinion on this, and if my theory makes sense to you!
Would love to see other opinion on this, and if my theory makes sense to you!