Fusion Material Monsters are monsters that are used for the Fusion Summon of a Fusion Monster. These Fusion Material Monsters are listed on the card. While Fusion Material Monsters are usually specific monsters, occasionally, the required monsters are more vague, such as Five-Headed Dragon, simply requiring any 5 Dragon-Type monsters to Fusion Summon it.
You can also use Fusion Substitute Monsters, such as "The Dark - Hex-Sealed Fusion".
Gameplay and Glossary