Natural 20 and Natural 1 Rules

Critical Hits and Fumbles (Attacks & Spells)

Natural 20 on an attack: Roll damage normally, then add the maximum possible result of the damage dice on top (not rerolled), plus any static modifiers once. Example: 1d8+2 becomes 1d8 (rolled) + 8 (max) + 2.
The same math applies to spell damage when a target fails a save with a Natural 20.
Natural 1 on an attack: No mechanical penalty. The player describes how it goes wrong narratively (dramatic, comedic, whatever fits the moment).
These crit and fumble rules apply equally to enemies, not just player characters.

Natural 20 on a skill check: Best possible outcome, provided success is actually possible given the fiction. It does not bypass physical impossibilities.
Natural 1 on a skill check: Not an automatic failure; represents bad luck rather than incompetence.
Only rolls called for by the DM count. If the DM doesn’t call for a Perception check, you cannot roll one yourself and declare it applies.
Passive Perception, Investigation, and Insight will be used throughout this campaign. Keep this in mind when building your character (ability scores, skill proficiencies, expertise, etc.).