Gray Norton.

From the black coral rooftop, Gray observed the enormous palace of House Valerius, one of the most powerful families in the underwater kingdom.
That night he hadn't gone to negotiate. He had gone to steal.
Perfectly concealed beneath a dark cloak, he gazed at the window of the treasure chamber. There rested the Pearl of Eternal Tides, a relic capable of controlling the ocean currents of the entire kingdom.
According to the nobles, it was a symbol of prosperity. According to Gray, it was a tool that should never have belonged to a single family.
With a silent movement, it slid down the palace walls. The guards barely had time to react before being trapped by currents of compressed water.
No injuries, no deaths. Only obstacles removed from their path.
Finally, she reached the main chamber, where the pearl floated in the center of a golden pedestal.
More beautiful than I imagined... Gray murmured softly, observing the pearl
"And more dangerous," interrupted an unknown voice.
Gray turned around. And standing motionless before him was that unknown warrior who had already ruined so many of his plans.
The black armor covering her enemy's body appeared to be made of metallic scales. The helmet had a sharp shape, resembling a shark's head, with a fin running along the top and two bright crimson eyes that gleamed in the storm.