2006 · ソースブック（プレイを拡張するルール／オプション）

Advanced d20 Magic

This sourcebook presents a skill-based magic system for d20 role-playing games, replacing traditional level-based spellcasting. Spells use casting slots and have difficulty and drain values; Fortitude saves determine whether casting succeeds, while failed checks can require additional skill checks to maintain control. Casters can reduce drain by naming a spell, extending its casting time, or performing a ritual. The book includes rules for countering and combining spells, feats, class conversions for d20 fantasy games, spell-conversion guidelines, and hundreds of converted spells. It also supports anime-inspired magical campaigns and use with settings such as BESM d20, d20 Modern, and d20 Future.