In last night’s game, while the party was fleeing a horse-sized giant scorpion, stalwart party member Martin “le Black” held the back of the line to give the others time to flee up a stairway. His player asked me if he could get some bonuses to AC for fighting purely defensively, having the high ground, and being better able than the giant scorpion to maneuver through the close confines of the rubble-choked stair. “Sure,” I said. But it was late and I was tired, and I didn’t actually determine what the modifiers would be. I just rolled the dice.
The attack roll for the giant scorpion’s stinger was a 19. Was this a hit? I didn’t know. Probably it should have hit—almost certainly, really—but that was meaningless when I was deciding on the modifiers after the fact. If I’d chosen the modifiers beforehand, this would be letting the dice fall where they may. Now, however, it was pure DM fiat either way.
I thought for a moment. If the attack hit and Martin blew his poison save, I’d be killing a PC by fiat. If the attack missed, I’d be going soft on my players, and that’s a violation of social contract; the old school DM must be harsh but fair, and this would undermine that crucial harshness.What did I do? I split the difference, sort of. I let the attack hit but without the poison save; the giant scorpion’s stinger missed, but smacked Martin upside the head on the backswing for a few points of damage. Not much of a compromise, really, as he had oodles of hit points to spare, though it could have made a difference if the scorpion had gotten another set of attacks off before Martin clambered out of range. (Those two d10 pincer attacks can be nasty!)
In retrospect, the best choice would have been to discard that attack roll, solidly establish the ad hoc modifiers, and then roll the attack again. But I’m not embarrassed by my choice. Strictness isn’t a goal in and of itself; it’s a means to an end, and its goal is a more enjoyable play experience at the table. Player characters should never die for ambiguous reasons. Killing Martin while I was playing loosey-goosey with the rules would not have made things more fun.
The lesson I’m taking away from this is not that I need to be harsher, or that I need to kill off a PC to make up for it. The lesson is that letting the dice fall where they may only works if you know what the roll means before you let the dice drop.