In this chapter, we learn that the Blood Devil's secret weapon is the "blood devil secret manual" . This is a reference to the fact that the blood devil is the master of controlling blood and corpses. The Blood Devil is also a master of self-harming techniques, which is why he is so eager to learn the manual.
In this chapter, we learn that the Blood Devil's secret weapon is the "blood devil secret manual" . This is a reference to the fact that the blood devil is the master of controlling blood and corpses. The Blood Devil is also a master of self-harming techniques, which is why he is so eager to learn the manual.