Cythrons, I am hoping Runequest Slaine has a few more things to say about these demons.
I actualley brought a book relating to the Planescape universe and Sigil the city of doors. ( I think thats what it's called.) 'The Planewalkers Handbook.' It's got some great art-work in it.
Referring to one section about the playable Rogue Modrons in particular.
Being what they are, role playing one of these takes a unique approach.
One of the most interesting things I found out about these Modrons are that they made it a rule ( That can be altered slightly.) that the player only ever roles inititive once and using that very same number the entire time they are playing their character. Because of their precise and robotic nature, that can't break this procedure at all.
I would also make it a rule to too have them role a twenty sider against every armour value ( Thaco ) numbering from ten or twenty to it's negative counter part and use that number that they roled the entire time, while trying to hit anything of that same armour class value.
The same with Saving throws. Have them a role a saving throw for everything and keep the that same value the entire time they are been played.
So, it would be apity if they roled badly and had to use that same value each time. If a twenty was rolled. Well I guess the game might get little to boring after while. Somethings have to be left to chance.
http://www.wizards.com/default.asp?x=dnd/we/20010921a&pf=true