2005 · ソースブック（プレイを拡張するルール／オプション）
Indigo Magic (D20)
Indigo magic is the colour of the mind, focused on inner order, control, memory, and thought rather than traditional schools of magical effect. Its practitioners can influence others, erase awareness, and uncover memories, while the feared Skeptomancer manipulates minds through will alone. This supplement adds three Clerical or Mystical domains, reclassifies a selection of Player’s Handbook spells within Chromatic Magic Theory, introduces new spell effects, and presents the Skeptomancer as a dedicated mind-mage character class.
スキルベース（スキルを購入または獲得）属性／ステータス制（STR、CON、PERなど）レベル制（XPを獲得してレベルアップ）
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。