Dragon BreathHere's my thinking about figuring out how many people get hit by dragon breath in an abstracted combat. The first thing I thought of was: what percent of an arc around a dragon can its cone-shaped breath hit? For red dragons, the fire is a cone 9" by 3" in size. Here's a slice of half that area:
Since this half-area is a right triangle, it's easy to figure out the angle involved: about 9.5 degrees -- so the whole red-dragon cone is about 19 degrees, say 20 degrees for convenience sake. So that means if the red dragon was pivoting its head outward like a random turret it would only cover 1/18 of the surrounding disc, or 1/18 of an opposing party, at a time. That seemed far too little, so I looked for another approach.
The idea I thought then, was this; a smart party would want to spread out as much as possible on the dragon, but the dragon's body is long, so effectively you'll have half of the fighters on one side, and half lined up on the other side (optimally to the attacker's view). Assume the dragon can crane it's neck around and shoot a blast just scraping one side of itself without hurting itself. We know from physical testing that a red dragon cone can hit up to 14 figures in a sparse formation (link). So the conclusion was to rule that a red dragon's breath can hit half of the opposing party, to a maximum of 14 figures. The same rule was used for gorgons and chimeras, with a little math on the smaller areas to give a different maximum figure number (7 for gorgons, 4 for chimera).
Giant MeleeInitially I was surprised by some of the result from Monday, by how few low-level fighters it took to match up against fairly high-level monsters. For example: The table says it only takes 4 1st-level fighters (in chain & shield with a sword and +1 bonus) to be evenly matched against a Hill Giant (with 8 hit dice and a double-damage attack). So as a double-check I sat down and manually scratched out a case study.
- Giant average damage/round: 7 × 0.65 = 4.55. This gives about a 50/50 chance of the giant killing a man per round; if the fighter's hit points are 4 or below he's dead, if hit points are above 4 (on d8) he lives another round. That is: expect to kill a man every other round.
- Fighters average damage/round: 5.5 × 0.35 = 1.925. Say on average that each fighter tags the giant for about 2 hit points each round.
- Giant average hit points are 3.5 × 8 = 28 (OD&D d6 dice, as always).
Case 1: Giant kills no one with initial rock-throw. By melee round:
- Giant kills 0; 4 fighters do 8 hp damage; giant at 20 hp.
- Giant kills 1; 3 fighters do 6 hp; giant at 14 hp.
- Giant kills 0; 3 fighters do 6 hp; giant at 8 hp.
- Giant kills 1; 2 fighters do 4 hp; giant at 4 hp.
- Giant kills 0; 2 fighters do 4 hp; giant dead, fighters win.
- Giant kills 0; 3 fighters do 6 hp damage; giant at 22 hp.
- Giant kills 1; 2 fighters do 4 hp damage; giant at 18 hp.
- Giant kills 0; 2 fighters do 4 hp damage; giant at 14 hp.
- Giant kills 1; 1 fighter does 2 hp damage; giant at 12 hp.
- Giant kills 0; 1 fighter does 2 hp damage; giant at 10 hp.
- Giant kills 1; 0 fighters left, giant wins.
You could interleave the 2nd case so that the fighters get initiative on the giant (attack first in each round); they still lose, although it's a closer match, the giant having only 4 hp at the end. But in short the result does check out; the giant-vs-four-veterans matchup has about a 50/50 chance of going either way, depending on whether the giant strikes with its initial rock attack or not.