2013 · ソースブック（プレイを拡張するルール／オプション）
Underground Adventures
This supplement explores underground settings, from historical beliefs about Earth’s interior to modern scientific information and speculative ideas. It covers the hazards of subterranean travel, including limited senses and movement, air and water, and different types of caves. It provides five explorer templates, equipment and vehicles, new Talents, techniques, and spells, along with species descriptions and game statistics for fantastic underground creatures. Guidance for creating subterranean locations and campaign seeds supports adventures beneath the surface.
スキルベース（スキルを購入または獲得）ポイント制（ポイントを割り振ってスキルや能力を得る）ダイス（主にd6）
ゲーム情報（人数、プレイ時間、対象年齢、クレジット）の出典：BoardGameGeek。