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Portrait of Euan Reid wearing aviator sunglasses
Euan
Reid
Technical leader · Software engineer

Challenge Rating

A quick method for tuning ordinary enemies to the party facing them.

Originally devised for Dungeons & Dragons 5e, this is a quick way to tune an NPC to the party facing it. It sets armour class, hit points, attack bonus, and damage without relying on the game’s built-in Challenge Rating. It transfers readily to other d20 games, and often to other systems.

Set n to 0 for mooks, 1 for tough mooks, 2 for leaders, and so on.

  • Armour class: average PC attack bonus + 10 + n.
  • Hit points: (2 + n) × average PC damage.
  • Attack bonus: average PC armour class + n - 13.
  • Damage: (1 + n) / (4 + n) × average PC hit points.

This gives you mooks that are easy to hit and take a couple of blows to defeat, tough mooks that last a little longer while hitting harder and more often, and leaders that take about four hits to drop and can deal half a PC’s health in a single blow. The damage may seem a bit high at first – that’s because it’s tuned for a party with healing spells and potions, to give them a reason to use them. Note, this rule is intended for ordinary enemies – not bosses.