2.1 DM rules

This page is for rules that the DM must know but that aren't so important for players. Players are still welcome to read them, however.

Temporary hit points (THP)
Some effects grant temporary hit points. They stack on top of your regular HP and are lost first when taking damage. THP are lost after 1 minute (10 rounds). Receiving THP doesn't count as magical healing.

Ongoing damage
Some effects, such as poison, apply ongoing damage. This means you take the stated damage at the start of each of your turns, ignoring DR.

Rounding
Whenever a calculation results in a fraction, you always round down.

Effect durations
Effects with a set duration always end at the start of the turn of the creature who caused the effect. Effects with a duration of one round end at the start of the caster’s next turn, those with a duration of two end at the start of the turn after that, etc.

Environmental hazards
Below are a few common environmental hazards or inconveniences, and how they're resolved.

Darkness
For simplicity, there are two stages of lighting: light and darkness. Light is the natural environment of many creatures, so carries no special effects.

In darkness, your speed is halved, you take disadvantage on attack rolls and most checks, and provide advantage to attacks made against you. Creatures with darkvision can see normally in darkness, and don't suffer these effects.

Falling
A fall of 2 squares (3 meters) deals d6 damage. Every additional square increases the damage by another d6. Before rolling damage, you can make an agility (acrobatics) check. For every 5 points you score with that check, the damage is decreased by d6, to a minimum of 0.

Fire
If you enter or start your turn in a burning square, you take d6 fire damage. If you catch on fire yourself, you take d6 fire damage (ignoring DR) at the start of each of your turns until you take an action to stop, drop and roll, leaving you prone. For simplicity, creatures only catch on fire from special circumstances, such as being covered in oil and lit, never from exposure to normal fire.

Intoxication
Alcohol intake is measured in portions, an abstract measurement, the exact size of which depends on the drink's alcohol content. If you drink one portion of alcohol, you gain a +1 bonus to your str and con (your max HP raises accordingly), but a -1 penalty to your dex, agi and int. Every portion you drink on top of that increases the penalties by 1; the bonuses remain the same. You can drink 2 + half your con portions of alcohol before passing out.