Roger Zelazny was extremely good

[...] While it's difficult to imagine Roger doing anything as sublimely geeky as role-playing games, I'm able to record that he was very good at it. 

[...] Whether through observation, Jane's coaching, or his own repressed talents as an actor, Roger tended to shine i nhis roles. Initially he chose minor characters, a bit removed from the main thrust of the action, but nevertheless complete characters who had their own part to play. In a game set in feudal Japan, Roger turped up as the Chinese poet Li Po, a character who specialized in carousing and extemporaneous verse. The poetry that Roger recited on these occations had the geniune flavor of Li Po, too. 

In a starship adventure game, Roger appeared as a preacher named Shuyler. Chaplain Sky was a navy "xenochaplain", supposed to be able to minister to the spiritual needs of any conceivable denomination of human, alien, or the odd sentient rock. (He didn't do very well with the rock, actually.) The professional requirement to believe in everything led to Chaplain Sky's not believing in anything very much, and led to some of Gaming's Most Funny Spiritual Moments, as when Sky blessed some space marines about to hit the beach on an enemy-held planet. Sky's address went more or less as follows: 

"Insofar as I may be heard by anything which may or not care what I say, I ask, if it matters, that these soliders be granted luck and favor, regardless of anything they have done or failed to do which requires forgiveness. Conversely, if not forgiveness, but something else may be required to ensure any possible benefit for which they may be eligible, I ask that this, whatever it may be, be granted or withheld, as the case may be, in such a manner as to ensure them receiving said benefit. I ask this in my capacity as their elected intermediary between themselves and that which may not be themselves, but which may have an interest in the matter of their receiving as much as is possible for them to receive of this blessing, and which may in some way be influenced by this ceremony. Amen." 

From A Singular Being by Walter Jon Williams. 

 

No wonder the man's picaresque novels are so D&D-able.