I've seen many where the second lead is likeable, but never to the point where I have "second lead syndrome" (Which I think is stupid) and want the lead to end up with them because I know it's not their story. Are there any where the second male lead isn't a good guy? The female lead likes him though, but doesn't realize he's a bad person as the male lead who is good tries to convince her. She eventually does and then falls for the male lead.

Depending on what you mean by a bad guy, but Cruel Romance kinda has it.


Naming either of my recommendations below would technically be a SPOILER, so highlight to see ;-)



Missing You  and also arguably you can say Bridal Mask have it, but maybe not exactly what you're looking for.
Doesn't have to be straight up evil. He can be an unlikeable douchebag as well.

Also, I've seen the first one you mentioned and she never liked the 2nd guy like that.