Cha Hyun-su

After forcing the survivors and the group of criminals into the chalk circle, the leader introduced himself, then introduced the two he called his "dogs": Jung Wooi-myung and Leah. The two were his main subordinates, although in secret, both were monsters in disguise (something even their leader didn't know). Both were missing special infecteds who had escaped from the research laboratory, finding refuge in the church where humans killed each other, leaving the two of them as the last ones alive. Until they discovered that hyun-su was like them; the boss, not knowing that those two were as well, brought hyun-su and his entire group, leaving the rest of the building. Those who were on the red line were alone—only hyun-su. Some time after that, with wooi-myung's help, he killed all of them, and now hyun-su was about to do the same to leah.
Wooi-myung: she is like us