CallmeMISTER
Well, to be honest, your SI feels somehow completely useless. What did you do with math magic? For the sake of an Op cheat for your MC, you turned it into complete garbage, where does the cast time come from? a person with a perfect memory should not have any problems with fast casting, what other strange calculations do you derive? The essence of mathematical magic is that you reduce all the necessary effects to a ready-made formula, and you need to change or recalculate something only when you change or create new spell, I honestly don't understand the logic behind your magic system.
Actually, still confused about this calculation and core. He only have 7 core, 1 with permanent magic. The way he used magic from the start is to fill the empty core with some magic formula, not to calculate some formula. So logically, Mc only able to cast 7 kind of magic. But in the other times, he say that the core just like a chip core that used to do calculation. So, based on that argument, he can cast a lot of spell as long as he can do the calculation. I don't know how human use magic in DxD and how much the core of each magician, the things that i know are magician can use a lot of magic and Ajuka Belzeebub is the smartest and the greatest mage that use calculation for his Kankara Formula, and he is a devil not a human.
It is kinda egotistical how devils take over human land and use it as territory, stopping exorcists and other factions from doing what they want. How is human territory their's? The Shinto Faction seems to be the least dangerous faction. But sadly the West and East branch are separate and split making them weaker and divided. If I was the Shinto faction, I would have tried to stop the spread of Christianity and the Biblical Faction from coming to Japan.