Spoiler!
Was stopped by the 5 heroes but in like 5ish chapter from now we learned the blood demon was not defeated but instead sealed away by separating his consciousness, vessel, energy and his 5 senses and had then sealed in seperate location but he is so powerful his vessel and energy manifested and living being so wi seol ah is the living manifestation of the blood demons vessel and the heavenly demon is the manifestation of the blood demons energy the senses also have their own manifestation but I won't spoil it unless you ask