So this guy, they just exposed what magic he is using by showing this wand. This is a legit design. I had Astra analyse it. In the anime his spellcasting sounds like speaking backwards. This matches the function of this wand. It uses a complicated and bulky method where the result is studied first, then the intent which lead to this result. So you cannot achieve a result which you cannot study in its completeness, it is a reverse method. Normal spells work by taking your intent and aiming for the result, manifesting the result out as an expression of intent.

This magic works in the other direction, "the Texas sharpshooter" method. Look for the result occurring anywhere, be it seemingly random or by someone's intent, it doesn't matter. Then study all elements of intent which lead up to this result. Even if you think it's a random result, look at what intent is involved at some level or distance. Then relate the correct intents to this factually existing result.

By grabbing the right intents, the effect can then be re-manifested. It sounds like this is just a normal method of deduction, but to perform this instantly for any new situation requires a special kind of mechanic, and that is what this type of magic is about.