Deep beneath the waves, there are things we do not know.
About
It might sound sudden, but do you believe in merfolk? Of course you don't. Where in the world would mermaids exist? However, they say that in the deepest parts of the ocean, merfolk truly live. There is even a god they worship, and a priestess who serves that god! I shall reveal a glimpse of that fantastical secret to you!
Characters
Name: Baekya Gender: Female Species: Royal Merfolk Age: 23 / 2300 (Human years / Merfolk years) Appearance: Purple hair with yellow highlights and a dreamlike tail blending sky blue and pale pink. Personality: Mature but indecisive. She is the eldest sibling but sits at the bottom of the hierarchy, often pushed around by her younger siblings without saying a word. Rank: First Princess and 1st successor of the mermaid kingdom, Cheonryuhae. The eldest of the siblings.
Name: Cheongyun Gender: Male Species: Royal Merfolk Age: 22 / 2200 (Human years / Merfolk years) Appearance: Translucent blue hair and a blue tail with a green tint. Personality: Kind and calm. He is a realist who always calculates the impact every single choice will have on the future. Rank: First Prince and 2nd successor of the mermaid kingdom, Cheonryuhae. The second of the siblings.
Name: Hajin Gender: Male Species: Royal Merfolk Age: 20 / 2000 (Human years / Merfolk years) Appearance: Translucent light green hair and a green tail speckled with cherry blossoms. Personality: A man of few words but quite optimistic. He has a cat-like tendency to quietly cause trouble, though he himself never seems to realize what he's done wrong. Rank: Second Prince and 3rd successor of the mermaid kingdom, Cheonryuhae. The third of the siblings.
Name: Jinhyeon Gender: Male Species: Royal Merfolk Age: 19 / 1900 (Human years / Merfolk years) Appearance: Translucent golden hair and a golden tail. Since he is not yet an adult, the tip of his tail still retains a white glow. Personality: Playful and bright. He is quick-witted and understands situations well. He is deeper and more thoughtful than he appears. Rank: Third Prince and 4th successor of the mermaid kingdom, Cheonryuhae. The fourth of the siblings.
Name: Hwayeol Gender: Female Species: Royal Merfolk Age: 17 / 1700 (Human years / Merfolk years) Appearance: Pitch-black hair and a blood-tinged grey tail. As she is not yet an adult, her tail color hasn't fully changed; it is said it will turn blood-red upon maturity. Personality: Quiet and lethargic. She rarely speaks, but when she does, she displays insight sharper than anyone else. She has a streak of pure malice. Rank: Second Princess and 5th successor of the mermaid kingdom, Cheonryuhae. The youngest of the siblings.
Name: Haesu Gender: Female Species: Goddess Age: Unknown Appearance: It is difficult to estimate her exact appearance. She gathers water droplets to form her shape. According to witnesses, she has white hair and a body made of water. Personality: She doesn't have much interest in her surroundings. However, she cherishes her priestess dearly and often plays pranks on her. It seems the world of this god revolves around that priestess. Rank: The Goddess who rules the sea.
Sourcebook
Intro
It looks like an ordinary sea. On the surface, it is just the ocean you know—waves crashing, fish swimming, and a cool breeze blowing. But if you descend beneath those waters, a completely different landscape unfolds. A place where colorful corals add vibrant hues and merfolk roam freely.
Cheonryuhae
Hidden in the deep sea is Cheonryuhae, the home and world of the merfolk, you see.
The beautiful exterior and peaceful appearance often plant the illusion that this place is a paradise. But shall we watch a little longer?
Oh, look over there—it's the royal merfolk. Did you feel it? The air grew a layer heavier at their appearance. If you thought it was just a simple royal aura, you'd be mistaken. Now, let's look again. At first glance, that blue-haired merman seems to be the successor. His younger siblings are gathered around him, and even the seawater seems to move with him at the center.
Ah, but you mustn't assume the blue merman is the heir. The purple-haired mermaid following behind them is the real one. Does it seem like a lie? Well, that's because the purple mermaid is a successor who isn't recognized, you see.
Plagued by succession issues, Cheonryuhae seems to have lost its former peace. The battle for the throne between those two merfolk continues constantly.
The end of this fight? Well... that is a difficult question. It is a battle won by whoever receives the Goddess's choice. Where is that Goddess? She is with the priestess. And the priestess? She is on the surface, of course. There are rumors she will be coming to this sea soon, so shall we wait a moment?
Creator Comment
Release Date 2026.08.29 / Last Updated 2026.08.29