Tempestry

Tempestry is the magic of Water, fueled by the Titan Hydros. The Tempests are actually the rulers of Tenebrae, residing in the palace in the city centre. When threatened with death in ancient times, Hydros had to grant this power to the Tempests. There are many powers. Tempests can walk over water, breathe under water, summon or dissipate storms, and call lightning bolts or explosions. Since all of it comes directly from Hydros, no Words of Power, Reagents or other utensils are needed to do the magic.

Sadly, it is a inherited trait, and can't be learned, only granted by Hydros. In a attempt to do so, the Avatar made a deal and freed Hydros. But s/he was duped, and the power of Tempestry was lost for all time to Pagan.

Trivia

 * Originally, Avatar would've gained the powers of Tempestry after freeing Hydros but Tempestry was part of the cuts the original plot was subjected to. Powers of Tempestry would have opened new areas to explore in Pagan.