In Gravekeeper, how to quickly obtain the blood of the Gravekeeper can be referenced as follows:
Blood can be harvested through cadaver surgery, but it requires technological "software".
Place the corpse on the dissecting table in the morgue to dissect it and obtain blood, skin, bones and other materials. Materials can be used for research. There is a certain chance that the dissection will fail, and failure of the dissection will significantly reduce the aesthetics of the corpse.
