Intimidation is not, to my mind, about what the characters can do. It is what the target believes the characters can and are willing to do. It is subjective to the NPC's point of view.
Sometimes, what the characters can do is obvious - "I've already had Grond here rip off one of your arms. Talk, or I'll have him rip off the other one!" is likely to have some pretty major auto-successes or bonuses attached to it.
Sometimes, no matter what the characters can do, if the NPC knows for some reason that they won't do it (say, he knows the party cleric is of a deity who does not allow harm to come to those who have surrendered), then the threat is not credible, and there will be hefty penalties to the check.
And that's usually how I approach it - penalties or bonuses on the check, in whatever form is appropriate for the game rules I am using.
Sometimes, what the characters can do is obvious - "I've already had Grond here rip off one of your arms. Talk, or I'll have him rip off the other one!" is likely to have some pretty major auto-successes or bonuses attached to it.
Sometimes, no matter what the characters can do, if the NPC knows for some reason that they won't do it (say, he knows the party cleric is of a deity who does not allow harm to come to those who have surrendered), then the threat is not credible, and there will be hefty penalties to the check.
And that's usually how I approach it - penalties or bonuses on the check, in whatever form is appropriate for the game rules I am using.
