Comments of chapter undefined of My Life As The First S-Class Guide

so my guess is that the virus is now in seojin. The virus attacked seojin so his blood power would activate and used that to jump to seojin. It was already stated that song moonho's brother was able to use his skill to manipulate song moonho. if the skill is somehow linking the blood with a relative, the virus would be able to transfer. also why seojin doesn't remember actions afterwards.