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Hokuto no Ken: Raoh Gaiden Ten no Haoh is an anime about a major antagonist in Hokuto no Ken, and how he builds his realm in a post-apocalyptic world.
Hataraku Maou-sama! is a comedy about an 'evil' overworld from a fantasy world being thrust into the modern world, and how he deals with it. It turns out he's not really that evil. I've only seen the anime.
The manga Maoyuu Maou Yuusha - "Kono Watashi no Mono Tonare, Yuusha yo" "Kotowaru!" has a lot of chapters from the perspective of an 'evil' overlord who is, again, not really that evil. It's very detailed in terms of economics and politics, and is usually light hearted with appropriately dramatic moments. I haven't seen the anime or read the other manga adaptation.
The manga Helk is primarily from the perspective of 'demons' as they fight against humans, and a few of the protagonists are 'evil' overlords. Yet again, they turn out to be not that evil after all. It's a comedy that becomes more dramatic as the story progresses.