One of the PCs was a paladin - a Buddhist warrior monk - who, in the course of play, took the view that the emperor of heaven and the lrds of karma were morally misguided, and that true compassion required him to turn against their dictates.
Another PC was a fox spirit, exiled from heaven and progressing from fox to human form contrary to the terms of his banishment - when the constables of heaven came to capture and punish him, the PCs defended their friend and fought the constables, the first of their steps on an indendent path contrary to the dictates of karma.
Other PCs were samurai, in various complicated relationships to one another, their families, the daimyo to whom their families owed fealty, etc. One of these spent most of the campaign courting a celestial dragon who was caught between the politic conflicts of her parents, one a sea lord and the other a storm lord, as well as the complexities of romancing a mortal when your loyaties are to the heavens.
This game was driven by questions of loyalty, duty, authority, legitimacy, freedom and justice. The application of pre-4e paladin code mechanics, or AD&D Oriental Adventures honour mechanics, would have killed it stone dead for no benefit at all.
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