Characters are awarded experience points (XP) for killing monsters and accumulating treasure. Monsters have a set experience point value (in the monster descriptions), and one gold piece is equal to one XP. It may seem odd to award experience for treasure, but keep in mind that every gold piece gained by the character is an index of the player’s skill. Awarding experience only for killing monsters fails to reward a party of adventurers that successfully lures a dragon away from its hoard so that its treasure can be stolen without a fight, and it fails to reward characters that operate by intelligence, stealth, trickery and misdirection.
Each character class has a Prime Attribute listed in the character class description. If this Prime Attribute is 13 or higher, all experience point awards to the character are increased by 5%. Additionally, if the character has a charisma score of 13 or more, experience point awards are increased by 5%. Finally, if the character has a wisdom score of 13+, the character gains a third 5% bonus. It is possible for a character to gain as many as three 5% bonuses to experience point awards.
When your character has accumulated enough experience points to reach a new level, you will roll another hit die and gain new spells if you’re a Magic-user or Cleric. Your combat skills may also increase. In other words, you’ve become more powerful and can pursue greater challenges!