This is Kain's most optimized form of magic skill usage.
Indeed, the way Kain built this isn't obvious at all.
It's the way a wise person systematizes a complex process or system. For instance, if there's a long theoretical passage to memorize, a normal student might try to cram it, often unsuccessfully.
In contrast, a wise student will synthesize and break it down, not just simply dividing the theory, but organizing it into something like a branching diagram or tree diagram, making the memorization of a dense theoretical system much more efficient.
Here, unlike ordinary Magus where more enemies lead to exponentially more complex tasks, and they accept it as part of their strategy, Kain doesn't. He optimizes his strategy to the extreme, breaking down targets for individual handling, but achieving far greater overall efficiency than normal.
