Blood is a biological tag for your genetic line. Signing in blood allows the demon to claim not just you, but your descendants. Use . Mortal, non-organic ink.
In almost all mythologies, breaking an infernal contract is nearly impossible, but clever mortals have occasionally found a way out. The Legal Loophole demon deals guide
Find a bigger demon. Sell them something else to buy out the first contract. (Warning: This is called "laddering debt" and it ends with you being a manager in Hell). Blood is a biological tag for your genetic line
In the TV show Supernatural , a kiss seals a deal at a literal crossroads, giving the summoner ten years before the Hellhounds arrive. Mortal, non-organic ink
The cost of a demon deal is never purely financial. It must extract a deep personal or mechanical toll.
You have summoned a demon. The candle flickers. The smell of sulfur fills the air. Do not scream. Do not run.