Taboo Manual for Raising a Succubus Girlfriend!

Can "Benbenjuzi" really deal with a bad-tempered girlfriend and save the world at the same time?
Sixty years ago, after the end of the Human-Demon War, a barrier appeared between the human world and the demon world, separating the two races and ushering in a brief era of peace.
A year ago, humans suspected that the demons were plotting an evil plan and sent one of their best fighters to the demon world to carry out a mission, but the man disappeared without a trace.
They could never imagine that the reason for the disappearance was simply because...
She has a cute demon girlfriend.
Now, a year later, humans are taking action again.
Next, she will face:
An ex-girlfriend who could nuke the demon world at any time.
A rookie descendant sent by humans to carry out a mission.
The daughter of the most mysterious demon ruler.
And his bad-tempered succubus girlfriend.
Anyway, do your best... Magical girl, Yoshito.