Personally, I think there are two kinds. First of all, the first rule is to be handsome. Behaviour is more natural and unrestrained, and there is an ambiguous behavior (relationship) with the female (male) host. It's hard not to circle powder, okay? Then the second is that the villain is a man with brains. He knows exactly where his goal is, not just as a role to promote the development of the plot. Maybe it will be whitewashed in the near future, but what he did should at least make me feel awe. If the director is better, it will give me a feeling of "ah, so it is such a person". Some of these villains are ugly, but their personality image deserves our respect. So Yan is not that important, so if there is a villain who pays equal attention to both, he is probably the protagonist.