Chinese hell scrolls not only offer a fascinating insight into Chinese religion; they also provide an avenue for examining the syncretic nature of religions generally. For example, Manichaeism spread out from Persia to Rome in the 4th century C.E., and there is evidence for its presence in Tang Dynasty China as early as 732 C.E. This religion adopted and adapted major elements of the other religions that geographically surrounded it, resulting in Jesus and the Buddha working side-by-side for the salvation of humankind. In Manichaean documents excavated at Dunhuang, the devout might choose to petition Yama because he was "really the compassionate thinking of Jesus." King Ping Deng directly figures into various Manichaean hymns as in the following extract from a piece pondering how a person's death exemplified impermanence, here translated by Tsui Chi:

Only the shameful deeds and the evil doings
Will become burdens on his back after that day of impermanence:
Before the King of the Balance [i.e. King Peng Deng] all his reasons are unjustifiable,
And he goes through transmigration for birth-and-death tortures,
Once again to be bound and controlled by the king of devils,
And grow gradually in impurity if no good chance is met:
He will enter the earth-dungeon (i.e. hell) or will be burnt out,
Or will be imprisoned with the devils, in eternal prison.
Songs and pleasure, dancing and laughter, and all music,
Eating and gorging a hundred delicacies, and management of lands and houses
Are like visions in a dream which disappear when he wakes -
Think carefully, and nothing seems reliable.
The temporal relations of a family, which are a mundane truth,
How far do they differ from that of staying at a travellers' inn?
Masses of persons stop and rest together for a night;
In the morning, they separate and return to their own lands?
Wife and concubine, sons and daughters are like creditors,
All existing because of mutual injuries in the past;
They are all enemies and robbers with affections,
And one is therefore bound to repay them their strength.

Elsewhere in the Manichaean texts, the good who come before King Ping Deng are led off to a place "where in the land roads are flat and even, and the sound of Sanskrit chantings spreads round, continuing and hovering." That description closely echoes the Western Paradise or "Pure Land" of Amitabha Buddha, and modern versions of King Ping Deng's hell indeed show a bridge leading off to the Western Paradise, a bridge that was part of the first hell in this particular series.