The Last Days of Hitler in the states used the title Downfall. It is an eerie movie, making Hitler seem personally sympathetic, which he may have been.
Regarding despicable characters, Hannah Arendt's Eichmann in Jerusalem is subtitled A Report on the Banality of Evil. I haven't read it in decades, but her point is that evil is often engendered by banal men (and women) not monsters -- clerks and petty bureaucrats.
As with Hitler, these people are extremely difficult, in my opinion, to nail down in fiction. But the lesson, I think, is that fictional despicable characters can be written with recognition that there may be a multidimensional common-person element within them but often are written as larger-than-life evil people as they are in thrillers and mystery novels, such as in the Jack Reacher stories.
The upshot of this rather rambling note is that the presentation of despicable characters will depend largely on the intent of the writing.