A quarrel between two powerful fey of the first water and fire fey. When banished they became mortal and lived out their lives. Problem is 13 generations past and the fey blood will spark within their last living decendents.
"What!?" screamed Aqua, her liquid hair turning into a stormy sea. "You don't have the power to banish us!"
"I rarely agree with my arch-enemy, but she is quite right," Valca added, his flaming hair crackling and the heat from his skin scorching the floor.
Aqua looked at the damage he was naturally creating and flicked a finger, putting the flames on the floor out.
"Fire fey," she sighed. Valca growled and was about to step forward when the large oak doors cracked open. They both gasped while everyone else knelt at the sight of Light. Light was not a thing, but a person - the first light in the universe.
"They may not have the power, but I do," she said, her voice like a song, like the trickling of water, like a babies first cry. The crackling of the first flame. Oh, you could go on and on about the sound of Light's voice.
"But... Light-" Aqua began to protest.
"Silence, Aqua. You and Valca misused the life I gave you here. You were my first creations and this is how you repay me?" she asked them. Sadness was clear in her pure bright eyes. Aqua and Valca looked turned their faces to the ground.
"But... if you banish us, Light, who will tame the fire?" Valca asked.
"Or the waves of the water," Aqua added.
"You will be replaced. Like mortals after they die."
"Wait!" Valca jumped in.
"You mean to send us to the mortal world-" Aqua said with fright.
"And replace us with our 13th generation? They won't know anything!"
"And who will govern while we're gone?"
"Your councils will rule till an heir shall rise."
Light said, and flicked her hand. To the people in the room it seemed that a flash of light consumed the rulers of Fire and Water, making them vanish. But in truth, Aqua and Valca fell through a tunnel of light, into the mortal world."