What options have people explored for a poison damage catagory?

A few ideas I've come up with off the top of my head:
Lethal Poison
Use the damage chart appropriate to the method of application with the addition of X lasting, 1 dealt each round of combat, where X is the demon's power, or a GM assigned strength of the poison.
Non-Lethal Poison
X lasting, with 1 dealt on application, and one dealt every hour after that, with X as above. Only deal every second point if target is resting for each two hour block
Or:
-X to Stamina for the purposes of endurance, maybe some other stuff as well.

But of coruse, I haven't run a game yet, so I don't know if this would be too overpowered.

Hi there,

I think a simpler approach is probably best ... use the Special Damage rules, and state the time of the effect as a constraint. For real-world, i.e. non-demonic poisons, one might simply look it up in a reference book to see the time course and methods of treatment, or whatever.

For demonic abilities, just make it up - "this damage kicks in the next day and gets worse hour by hour," or something like that. As long as the specific poison effects (a) are quantified by the Special Damage, and (b) represent a limit or constraint rather than an advantage of some kind, then you're good. If you want the effects to be advantageous, then another ability is probably called for, perhaps Cloak.

Best, Ron