Reiwa no Kusozako Kyuuketsuki Oji

A long time ago... In an age when non-human creatures emerged from the darkness to suck blood and roamed the land. There was a ruthless and arrogant king of a vampire clan who plunged people into the depths of fear. Time passed... and now it's the Reiwa era. The vampire king has become nothing more than a mere "uncle," with no trace of his former majesty. Abandoned by his wife, children, and entire family, this feeble uncle is struggling to even secure servants. Then, he suddenly comes up with a brilliant idea. "Why not turn that guy (the human man) I captured on a whim into a servant?" But that was just the beginning. Now, the curtain rises on a "reverse domination" by humans, who were once dominated! (Source: DLsite, translated)