The quest binding the blood members of the naga court — which excluded the merely married-in Rishi.
Referenced as the reason Rishi survived: because he was not a blood member of the naga court, he was not part of the whole Sepsis Whore quest that consumed Princess Vinata and the rest of the royal family. In real life he was married to a distant cousin of the royal family, close enough for status but not for the quest's grasp.
That technicality left Rishi free to bury himself outside the castle and emerge afterward with a contract in his inventory, rather than dying with the rest of the Blood Sultanate in the Temple of Khepri.
The blood-bound quest that defined who among the naga court had to die.