Rulebook · Chapter 12 of 17
12.0 Gaining Experience
General Rule
Experience (in the form of points) is earned in combat, by defeating monsters.
The total amount of experience gained (number of points) may, at the end of the game, decide individual victory for one of the players. Experience may also be spent to increase a character's various stats.
Procedure
The total experience points earned in a fight equals the sum of the strength stats of all monsters killed, multiplied by 6. This total is divided (however the players decide) among the surviving party members. Fractions are rounded down.
Every character sheet must keep a running record of the total experience points earned by that character since the start of the game.
If the game consists of multiple adventures (i.e. the characters enter and leave the maze repeatedly), experience points may be spent to increase a character's various stats.
Detailed Rules
[12.1] Monsters under a Charm effect fighting in the party's ranks do not gain experience; experience for the opponents they kill goes to the characters instead.
[12.2] After an adventure ends (upon leaving the maze), a character may "spend" 100 experience points and 100 gold pieces (or the equivalent in valuables) to raise one of their stats by one point (see 17.5). By spending the appropriate multiple of these sums, several stats can be increased, but each only by one point. So strength, resistance, proficiency with one weapon, an ability, or one component of magic potential may be increased (if a character wants to increase all three components, they must spend 300 experience points and 300 gold pieces).
The character sheet should record the number of experience points and gold pieces remaining after paying for stat increases.
[12.3] Agility may be increased just like the other stats, but it "costs" 150 experience points and 150 gold pieces (or the equivalent in valuables); see 17.5.