prerequisites, such as certain feats or membership in a specific organization. Prestige classes offer a focus on different abilities that may be difficult to attain otherwise; for example, the 3rd edition version of the Assassin prestige class grants minor magical powers, more sneak attack damage, and better usage of poison. The 3rd edition Dungeon Master's Guide included prestige classes such as the Arcane archer, Blackguard, Mystic Theurge, and Shadowdancer, while the 3.5 revision additionally included classes such as the Arcane Trickster, Archmage, Dragon Disciple, and Duelist. Many other sourcebooks introduced additional prestige classes, such as the Bladesinger in Tome and Blood; Blighter, Geomancer, Shifter, Verdant Lord in Masters of the Wild; Divine Champion in Forgotten Realms Campaign Setting; Cerebremancer and Elocater in Expanded Psionics Handbook; Fochlucan Lyrist in Complete Adventurer; and Chameleon in Races of Destiny. Some of these classes were readjusted for balance in the 3.5 revision of the game. Dungeons & Dragons 4th edition Core character classes The 4th edition heavily retooled the class system in favor of a more unified set of mechanics for characters, which was in part intended to reduce some of the perceived imbalance between spellcasters and non-spellcasters in the 3rd edition. Classes can be defined as the combination of a character role with a power source and are differentiated by what active-use class features and powers they give, all of which follow the same pattern of at-will, once per encounter, once daily, and utility powers. The 4th edition Player's Handbook does not include some classes from 3rd edition, such as the Barbarian, Bard, Druid, Monk, and Sorcerer (though these classes returned in the second and third volumes of the Player's Handbook), but does include the Warlock (originally introduced the v3.5 sourcebook Complete Arcane) and Warlord (originally introduced as the Marshal in the 3rd edition Miniatures Handbook) which had not appeared in the Player's Handbook in previous editions. Twenty-six classes were released in total. Power sources Different classes draw on different power sources for their abilities. The power sources used by the Player's Handbook classes are arcane, divine, and martial. Arcane classes gain magical energy from the cosmos, divine classes receive their power from the gods, and martial classes draw power from training and willpower. The Player's Handbook 2 introduces the primal power source, which draws power from the spirits of the natural world and features transformation as a theme. Dragon No. 379 included