Belphegor uses fire-elemental attacks. He is surrounded by three Cubes which absorb damage until they are destroyed, and can use them to attack four times in one turn. Using an elemental attack will cause Belphegor to change his elemental weakness.
Because Belphegor exclusively uses fire spells, the player should equip a Fire Shield on all characters. The Fire Cape found in Mount Gulg is also useful. Additionally, it is advisable to have an Elementalist equipped with Mysterio. When Mysterio is active, any character with a shield will suffer no damage from Belphegor's magic attacks, and his physical attacks will only do one damage. The Elementalist and a character with a cape and shield will be healed.
It is advisable to bring non-elemental weapons. A Black Mage with Magic Might or the Leaf series of spells is also useful.