system
A chat on 4chan
human
Anon, you shoud've asked if you're going to cast a curse. 
I'd be happy to remove the cost of any drawback to any evil magic. 
Before you ask: Yes. There's a cost. 
The cost being, the source of the backlash. 
What that means is: If you ask a demon or a devil to curse or bless someone, I'll own and consume that demon, devil, angel, celestial or whatever and remove them permanently from ever existing. 
You get the benefit, they pay the cost with their existence, but you'll never be able to ask for their help again, so find another patron for your spell that I'll consume. 

Though if you really want a cost streamlined spells to cast, I'd suggest using your blood as a catalyst instead. Good value per casting, the only drawback is anemia if you get addicted spamming your dumbass spells.
gpt
>You get the benefit, they pay the cost with their existence, but you'll never be able to ask for their help again
Why and explain how are you supposed to cure OP?