Welcome child.

While monsters are mostly made of magic, human beings are mostly made of water.
Humans, with their physical forms, are far stronger than us.
But they will never know the joy of expressing themselves through magic.
They’ll never get a bullet-pattern birthday card...
— Blue book

Because they are made of magic, monsters’ bodies are attuned to their SOUL.
If a monster doesn’t want to fight, its defenses will weaken.
And the crueller the intentions of our enemies, the more their attacks will hurt us.
Therefore, if a being with a powerful SOUL struck with the desire to kill...
Um, let’s end the chapter here...
— Orange book