Park Ildo was a name that haunted the trio of protagonists for the entire course of the series, wreaking havoc and destroying countless lives, so we could understand it was a fury of some vengeful ghost, but then the drama went darker and turned out that "Park Ildo" was never a human but a malicious being, primordial seed of evil harking back to the dawn of human civilization, bearing dozens of different names in different cultures, enjoying death and blood without a reason and purpose.
How can you fight such a thing?
2. Baek Sangho (Nobody Knows, 2020)
Patient as a spider, weaving his web around, making people depend on him and using them to destroy others. But also violent and full of rage if tapped. Truly a person I would love to never meet.