Elemental masters conquering nations or even realms

Asleep_Solid_9219's post got me thinking about the power of Shockwave. Zeatrix inherited the power from Levo. Where did Levo get it from? Did the former master die without passing the power down? Did an elemental master marry into the family? Or... Has the power been in the imperial family for generations? All the way from the first emperor perhaps? Is that how they became the imperial family in the first place? The thought of an elemental master ruling seems so obvious when one thinks about...