There's too much plot for it to be a pure hentai, but too little plot for a proper supernatural action series.
To call the characters one dimensional would be an insult to straight lines.
Every single bit of time that could have been spent on plot or characters is instead wasted on rapey sex-scenes.
You can almost set yourself a timer for when a sex-scene will occur (tip: it's all the fucking time, usually for no reason).
I can almost hear the guys in the studio animating this going "Oh shit, no one fucked for like a minute and half, can't have that"
It's a shame too, this could have been a Devilman-styled demon-centric action/horror show. Instead it's just ... nothing really.
Overall:
If all you want is to watch a bunch of, admittedly reasonably well-drawn, girls get raped by demon tentacle-dicks and then get blown to gory bits afterwards, this is the show for you.
If not, steer clear of this mess.
