2003 · ソースブック（プレイを拡張するルール／オプション）
Secrets of the Unicorn
A dual-system sourcebook for the Legend of the Five Rings role-playing game and its d20 counterpart, focused on the Unicorn Clan of Rokugan. It details the clan’s history, traditions, holdings, families, customs, and travels beyond the Empire, with maps and background for locations such as Outsider Keep. Players gain new schools, techniques, feats, and abilities for Unicorn characters, including the Khan’s Three Armies. Primarily intended as a Game Master resource, it includes adventure material, new fiction, metaplot updates, and secrets concerning the clan’s mysteries and conspiracies.
キャンペーン設定（ゲーム世界）レベル制（XPを獲得してレベルアップ）ダイス（主にd20）グリッドベース（移動/戦闘に正方形のマスを使用）
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。