Lawful evil patron: the blood god
When someone is killed, a warlock whom follows this patron has 60 minutes (10 turns) to make cuts on the body and start a ritual latsing 1 turn on them.
When finished, a red oozy looking hand spouts up from the ground and grabs them (smaller hands pop up for parts that have fallen off) bringing the now once aigain alive victim tothe realm of the blood god.
In this realm, the victims blood will be harvested from where the warlock made the cuts. This will last forever with no one ever to ve seen.
There is no death in this realm, but hunger, thirst and fatigue are very real, and the people in the realm will feel it for eternity.
This realm is also almost infinite, and grows with every person inside, no one sees eachoter, but can anly hear the screams of their brothers in fate.
The bloodgod is somwhere inside of this realm, laughing and taunting the victims of his design, killing him would be the only way to end the miserable existence of the people inside of the realm, but this will prove to be difficult.