For the item from Fire Emblem: Thracia 776 with the same function, which is known as "Master Seal" in more recent fan translations, see Knight Proof.
The Master Seal (Japanese: マスタープルフMaster Proof) is a class change item which properly debuted in Fire Emblem: The Sacred Stones, after a false start in Thracia 776 that saw it go unused and without functionality there. In all of its proper appearances, of which the only game since its proper debut it did not appear in is Echoes: Shadows of Valentia, it is used to promote almost all basic classes, typically excepting the Lord and Lord-like classes and some other special classes. In Fire Emblem: Three Houses however, due to the overall redesign of the Class change mechanic, it instead allows a unit to attempt a class change exam into a master-tier class if they are Level 30 or higher. In the majority of its appearances it is the sole class change item: exceptions include The Sacred Stones, where it is a less common alternative to the individual class change items; Path of Radiance where, while it is the only class change item, anyone can promote without one by reaching level 21; and Radiant Dawn, which includes the Master Crown and Holy Crown to promote to third-tier classes, but is otherwise the same as Path of Radiance.
Tsubasa's 3rd side story • Touma's 3rd side story • Yashiro's 3rd side story • Tiki's 3rd side story
Treasure Chest
Illusory Daiba Studio LCD panels area • Sealed area of Illusory Daitama • Sealed area of Illusory Daitama • Sealed area of Illusory 106 (x2) • Sealed area of Illusory Shibuya • Sealed area of Illusory Daiba TV • Sealed area of Daiba Studio • Illusory Dolhr
• Master Proof. Used in most games. • Highest exam pass. Used in Three Houses.
Spanish
• Sello maestro • Sello supremo
• Master seal. Used in most games. • Supreme Seal. Used in Three Houses.
French
• Magister • Sceau suprême
• From Magister, an academic degree used in some tertiary education contexts in Europe and South America. Used in most games. • Supreme Seal. Used in Three Houses.
German
• Meistersiegel • Ultimasiegel
• Master seal. Used in most games. • Ultima Seal. Used in Three Houses.
Italian
• Sigillo supremo • Sigillo master
• Supreme seal. Used in most games. • Master Seal. Used in Three Houses.