[Inigo Montoya]

How do I make my mages more powerful in magic? There are only 5 ways.
1) Empowerment - infusing the commander with gems at a laboratory - permanently increases his level by one in that path.
2) Forging a magic item like Earth Boots and giving it to the commander increases his level, but only if he already has magic in that path. In other words, giving Earth boots to an Earth-1 mage makes him an Earth-2 mage, but giving them to a Fire-1, Earth-0 mage does nothing.
3) Casting a spell at the beginning of combat like "Summon Earthpower" will increase the mage's Earth level for the entire battle. Communion or Sabbath Master can also boost magic levels. All enhancing spells cast in combat are temporary, and none have any effect after the end of combat.
4) Putting gems in the mage's gembox allows them to use gems during battle. Some spells require gems, but even "free" spells can use gems... specifically, if an Earth-2 mage wants to cast the Earth-3 spell Blade Wind, he can use an Earth gem from his gembox to boost his level to 3 for that one casting only. Mages run out of gems fast, though, because the AI uses them whether it needs to or not.
5) Holy and unholy "magic" can be increased by making the priest into your prophet.
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Actually, there is a 6th -- Wishing for Magic Power.