You can’t really have a great anime hero if you don’t have a great anime villain. This is why most of the popular shows, especially shounen, have this symbolic hero vs. villain scenario where each is fleshed out and amazing in their own right.
Japanese anime villains often have emotive traits and use symbolism that isn’t necessarily present in other types of animation. Particularly when contrasted to Western media, anime characters (whether heroes or villains) are portrayed with traits that are more realistic and/or less comical. Due to the fact that manga gets translated into anime and vice versa, this frequently overlaps with Manga Villains.