I can't say that I haven't encountered something like this before, although the concept is popular. And the fact that they decided to implement it deserves praise.
But it would have been better to look at the Strugatsky brothers and create U Janus and A Janus – such a split personality would be 10 times bolder and more powerful
Both from a lore-fantasy point of view, and because this trope isn't particularly used (I don't know of any examples, except for the original source). But what can you do.Regarding the strength of specialists, even specialists in individual spells are traditionally often quite good. Well, in 50% of cases, at least, remembering the same trio. A specialist in an entire school, like our hero, simply has to be powerful.