2009 · ソースブック（プレイを拡張するルール／オプション）
Alien Creation Guide
A supplement for Modern d20 campaigns that provides rules for creating balanced, playable alien species. Players and game masters define a species concept, adjust ability scores, and purchase traits such as wings, claws, special attacks, psionic powers, skills, and feats with creation points. Drawbacks provide additional points for customization. The guide also includes advice for developing communication, appearance, society, culture, aggressiveness, independence, determination, and technological development. Sample races, species templates, and racial levels for more powerful species are included.
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。