This immensely popular h-series has been said to have changed the history of adult animation with it’s scenes of violence, perversion and lust, filled with hardcore sex and unusual sexual fetishes! It consists of three different anime titles each with their own series of releases; Isaku, Shisaku and Kisaku. They are named after the three sadistic brothers whom they are about.

Why is Johan Liebert considered to be the best villain in anime, ever?

Johan Liebert.
Where do I begin? Firstly, he wasn't any different from any human is.
He doesn't have any super powers, no Super Saiyan, no Getsuga Tenshou, no Gear Fourth, no Sage mode.
None of these.
What he has is human abilities.
And yet he is scary. 1.
He MAKES people serial killers. 2.
He makes said serial killers do his bidding. 3.
Said serial killers are scared of just even hearing his name. 4.
He talks people into suicide. 5.
He's basically a phantom.
People don't know he exists. 6.
Everything he does (kills, burns place down, etc), he is unwavering on the decisions. 7.
Best of all, after killing a person, he doesn't flinch the least bit.
No reaction whatsoever.
Just like killing a mosquito. Everything he did seems realistic, what a human could do.
And the fact that everything is realistic makes him THAT much more scarier.
Would we be scared of an Aizen? Or a Frieza? No because we know for sure that even if they exist in some corner of the universe, we would have a 0% chance of meeting them.
But someone like Johan Liebert possibly could exist among us, living as a normal likeable citizen.
The realism is what makes him that good and that much scarier.