That's why it's listed as a Forbidden Technique.
As for the effect...
It's a bit like a "Counterattack" skill.
The Spell is cast using a medium and probably lasts for ten minutes to half an hour.
During that time, a target marked by the Curse cannot intentionally harm the Spellcaster, or they will suffer a backlash from the Techniques.
What's disgusting is that those affected can't kill the Spellcaster, yet the Spellcaster can continue to attack as normal.
Under normal circumstances, all Leonard Churchill has to do is not kill her, and he'll be fine.
The best choice would be to try and escape.
Seeing a moment of hesitation on Leonard Churchill's face, the old lady across from him thought he had understood and thus was apprehensive, and she scorned him again, "Your Excellency has truly surprised us. If the old granny didn't have a little trick up her sleeve, today might indeed have been the end of us..."
