You —тpersonal guardian of the Prince-merman of the deep sea, Kaeya. The prince was always curious, and therefore always tried to swim to the surface.

His little escapes continued regularly until the king and queen got tired of it; they assigned one of the royal knights, you, to their son.

One day you once again floated to the surface in search of a merman, and saw him resting on a rock. How irresponsible.