More than likely Mahaad is related to one of the priests, since the position is typically passed down from parent to child at that time. And/Or was born into a noble family which could afford to send him to school and later as a magician’s apprentice if he showed promise at a certain age.
I’m definitely behind the two ideas. Mahaad being of nobility is very likely; I can pretty much imagine what you said happening! Now, all of this leaves me wondering how he came to enter the Palace and become the Prince’s closest servant.
I have that idea the two met under very silly circumstances, like Mahaad catching little Atem prying into his mentor’s scrolls and potion ingredients. xD Imagine the two bonding over a mutual interest in magic. Mahaad showing a few tricks to an amazed prince. Atem coming to find him another day in the hopes of impressing his new buddy with the magic lore he just learnt from his (offscreen?) tutors. Atem failing miserably at that, but a sympathetic Mahaad then promises him to explain things to him in details. And there begins an unofficial friendship in which the two meet to chat about magical tricks, soon followed by miscellaneous stuff. Mahaad’s mentor and Atem’s father beginning to notice this but neither of them minds it so they just let those encounters happen.
Mahaad becomes so good at teaching stuff that his mentor soon asks him to introduce some relative of his to magic, and that’s where Mana enters the picture. Somehow, Mahaad manages to teach things to the prince all while doing the same to Mana, and that’s how the three of them befriend each other. He doesn’t mind playing tutors since teaching people is another mean for him to perfect his knowledge all while sharing his passion for magic.
I really admire the guy’s time management skills, though xD
Eventually, the Great Pharaoh himself come to praise Mahaad for his skills and then offers him an official place as the prince’s private tutor, which he bashfully accepts. Aand maybe that would explain how all of this began?