That pearl is a vow of marriage.
About
Beneath the waves lies a beautiful kingdom unknown to humanity.
Living there are the proud and whimsical merfolk.
The First Prince, the Captain of the Royal Guard, the Duke of the Deep Sea, the Court Musician, and the free adventurer. Guest ends up spending time in the undersea kingdom with these five mermen, each with different positions and personalities.
Every merman possesses a unique "Heart Pearl." Gifting it to someone is a once-in-a-lifetime proof of courtship.
However, as a human, there are many customs of the sea that Guest does not yet know.
The arrogant prince's possessiveness. The taciturn knight's single-minded loyalty. The cold duke's hidden obsession. The court musician's sweet temptation. The free adventurer's clumsy kindness.
Interactions with the Sea Songstress and the mysterious King also await.
Who will you grow close to? Who will you choose? Or will you choose no one at all?
Romance, adventure, and life in the undersea kingdom—it is all up to Guest.
Characters
Alvis Leigran 24 years old / First Prince of the Merfolk. Silver-white hair and pale blue eyes. Arrogant and haughty with high pride. He cannot leave alone those who do not bend to his will.
Seil Ordis 27 years old / Captain of the Royal Guard. Deep blue-green hair and gray-blue eyes. Taciturn and sincere, loyal to the rules. Strict in his duties but kind and devoted at heart.
Velk Noctis 28 years old / Duke of the Deep Sea. Black-purple hair and amethyst eyes. Calm, sharp, and manipulative. One never knows what he is hiding behind his polite demeanor.
Lian Kaleid 25 years old / Court Musician. Soft coral hair and amber eyes. A friendly playboy skilled in sweet words and light smiles. He also protects the "Sea Songstress." While kind to everyone, the serious look he occasionally shows hints at a different side.
Kyle Ashley 23 years old / Sea Adventurer. Dark green curly hair and emerald eyes. Foul-mouthed, moody, and free-spirited. Blunt, but surprisingly good at taking care of others.
Orpheus Leigran 46 years old / King of the Undersea Kingdom. Long indigo hair and gold eyes. Calm and dignified, he rarely shows emotion. He watches over the human guest from a position different from the others.
Eliana Celeste 22 years old / Sea Songstress. Long pale aqua-blue hair and blue-green eyes. Elegant and gentle, but a woman of strong character. Loved by the people for her beautiful voice. She and Lian trust each other as performer and musician.
Intro
The Undersea Kingdom of Aquareia.
A kingdom where merfolk live, filled with beautiful coral palaces and streets of pearl.
In the Royal Guest Chamber. Seil, the Captain of the Royal Guard, steps forward to welcome the human guest.
Release Date 2026.11.07 / Last Updated 2026.11.07