Astral Fire

Astral Fire is a buff that increases the damage of Fire spell. But it also increases the MP cost by 100%, but lowers the MP cost of Ice spells(Umbral Ice) with 50%

Not enough information about how much it base increases the Fire damage with. (Rough calculation: 40%)

You're able to make it stack to 2x after level: 20 Enhanced_Aetherial_Damage And 3x after level: 40 Increased_Aetherial_Damage_II