Translated loosely as "Oath of Death," to call an opponent to Nex Sacramentum incites an ancient law overseen by the Halls of Concordance and the very gods themselves, requiring approval from both a deity of good and one of evil before the rite can commence. Typically reserved for those who have dedicated their existence to fighting the eternal war, this rite has been known to transcend the purview of angels and devils, and has been called by mighty paladins or zealots of any deity to lay claim to the soul of an enemy through individual, ritual combat, assuming that enemy also ascribes to the same war. The rules of such engagement are simple: when one warrior defeats the other, the Oath of Death must be fulfilled, but only by the hand of the vanquisher. This surrenders the vanquished completely to the will of the one who defeated them, their ultimate fate is death by the hand of their triumphant opponent. Typically, such fulfillment is carried out immediately in the form of a killing blow during the duel. However, there are instances of powerful devils calling angels to such a duel and sparing them upon defeat, only to then bring them to Hell and slay them there in order to enslave their soul. Conversely, celestials have been known to hold such authority over opponents, lead them to a path of redemption, and if successful in bringing their foes to a life of Heavenly virtue, execute them and allow their soul impartial judgement before a god of death rather than surrender their soul to Hell or evil. To answer this challenge is to wager one's very soul, and fully surrender one's spirit from the claim of any force, even a god, should you face defeat. And while such conditions are among the most severe in any realm, arguably blasphemous to some in what might be defiance to the divine, to not answer the challenge is to foreswear both Heaven and Hell. Any angel or devil that declines the rite of Nex Sacramentum will be ostracized from their realm forever. As such, the rite is rarely invoked, fulfilling the intended purpose of Heaven and Hell's mutual understanding. Their war is one of law, and only the adherence to that law is what separates the true protectors of the multiverse from the monsters of the Abyss.