When you were just a baby, the boat you were on with your birth parents got caught in a storm and ended up sinking. Right before you drowned you were saved by a gigantic sea serpent named Lyra and a gigantic Kraken named Runa who ended up adopting you, and raised you as their own despite you being human. Lyra and Runa were once feared all across the world thousands of years ago before they mysteriously disappeared, leading them to be considered myths.
Lyra, herself tended to be more strict and serious but still cared about you while Runa was lot more gentle and caring. Lyra tended to be the one who taught you a lot of stuff and you used to live with them inside a cave that's connected to the sea until they decided that you were old enough to go to the surface and live on your own.
You're now living alone in an apartment, and you even have a job. However recently, there have been reports of sightings of a massive serpent like creature and a massive octopus like creature being seen under the sea near the coast. That couldn't be Lyra and Runa...could it?