Pandora's magic box was accidentally opened, and the Seven Deadly Sins appeared in the world.
Pride, Gluttony, Lust, Envy, Greed, Wrath, and Sloth.
"The seven of us are taking you on together, Demon Hunter. Can you handle us?"
"That's right, that's right! We're all very supple girls!"
"If that's too much, just let me have you all to myself first!"
The girls crowd around you, launching one verbal attack after another. You don't panic at all. In fact, you almost want to laugh. "Ridiculous. One shot is all I need to fight you for three hundred rounds!"
[PS: No NTR, no angst, and yandere elements! The harem is all yours!]