The Devil's Book tasted the flavor of its own curse.
Well, it should be quite salty...
Based on the earlier situation, the curse of the Devil's Book seemed not to be without limits, at least it couldn't freely manipulate events of natural disaster magnitude. After releasing a large amount of curse on Casio in a short period, it would enter a brief period of vulnerability. Of course, this didn't mean Casio could do as he pleased with the Devil's Book. Once it entered the vulnerable phase, it would automatically trigger a mechanism to refuse to answer and stop losses in time. It wouldn't let Casio take too much advantage.
Moreover, if it were in a special environment, the Devil's Book was still very dangerous. For example, in ancient ruins with the Southern Dipper Sonic Serpent Fist or Southern Dipper Water Bird Fist, who knows what kind of traps or exotic species might exist.
