Hearing Anivia's answer, Roy was stunned.
Of course, he knew that the blood of frost demons could create undead creatures, but he really did not expect that someone would especially hunt down frost demons just for this reason.
Most living creatures had blood in their bodies, and the blood of most creatures only existed to maintain their nutrients and did not have any special effects. But demons had strange characteristics in their blood due to the chaotic and dark magic power in their bodies.
These characteristics were usually reflected in other weaker creatures such as humans, animals, and so on. When these weak creatures received demon blood, they would be corroded by the demon blood, causing their bodies to undergo a tremendous mutation.