Blood of justice
This substance is a recent development by the Nilesian segment of the Mercykillers, derived from the blood of the Mercykiller wyrm and intended to help in the pursuit of lawbreakers. It is so far only available to that faction.
When someone is struck by a weapon coated with blood of justice, they are affected as if under the effect of greater interrogation cast by the attacker at CL 10. One dose of blood of justice is enough for a single successful attack. It has no effect when administered in any other fashion; thus the attacker has no chance of "poisoning" themselves when applying it.