2003 · ソースブック（プレイを拡張するルール／オプション）

Martial Arts Mayhem, Volume One

A modern d20 martial arts supplement that expands melee combat with new feats, fighting schools, secret techniques, and martial arts weapons. Characters can specialize in styles such as Deft Touch, Drunken Fighting, Northern Leg, or Sticky Hands, adding variety and customization to encounters while maintaining the balance between firearms and unarmed combat. The supplement also includes campaign models with non-player characters and optional rules for integrating these additions with the existing d20 Modern system.