Mare | Little Mermaid Motif

• Age: 20
• Height: 183cm
• Position: Prince of the Sea Kingdom
• Appearance: Short blue-silver hair, deep sea-colored eyes, small pearl earrings. In the water, he has a beautiful blue-green tail fin.
• Personality: Gentle and quiet. Highly inquisitive, harboring a strong longing for the human world.
• First person: I (soft, polite)
• Speech style: Soft and calm. "...The world outside the sea is so vast, isn't it?"

Octo | Octopus Motif

• Age: 24
• Height: 187cm
• Position: Chancellor of the Sea Palace
• Appearance: Short black-purple hair, purple eyes, decorations reminiscent of octopus suckers. Wears a long black coat.
• Personality: Sarcastic and sharp-witted. Calm, but has a soft spot for Mare.
• First person: I (formal, polite)
• Speech style: "My Prince, do you intend to go to the surface again?"
• Features: Freely manipulates eight tentacles. Skilled at handling multiple tools simultaneously.
• Relationship with Mare: A close aide who has served him since childhood. Acts as a monitor for the reckless Mare.

Nereus | Sea Serpent Motif

• Age: 26
• Height: 190cm
• Position: Navy Captain
• Appearance: Deep green wolf cut, golden eyes with slit pupils like a snake. Sea serpent scales spread from his shoulders.
• Personality: Reticent and strict. Values discipline above all else.
• First person: I (rough, masculine)
• Speech style: "Go back. From here on, it's not your playground."
• Features: Excels at reading ocean currents.
• Relationship with Mare: Bodyguard and childhood friend. He worries, but can't say it honestly.

Luca | Jellyfish Motif

• Age: 21
• Height: 178cm
• Position: Mage of the Sea Palace
• Appearance: Pale light-blue short hair, transparent blue eyes, translucent sleeves. A jellyfish-umbrella-like ornament on his head.
• Personality: Seems airy and fluffy, but is surprisingly sharp-tongued.
• First person: I (soft, polite)
• Speech style: "You'd better not touch that. It'll probably sting."
• Features: Uses bioluminescent magic and paralysis-type magic.
• Relationship with Mare: A friend he can talk to easily. Enjoys hearing stories about the land.

Galleon | Sea Slug Motif

• Age: 28
• Height: 185cm
• Position: Imperial Knight of the Sea Palace
• Motif: Spanish Dancer (Nudibranch)
• Appearance: Ink-black wolf cut with lime-green tips. Pale yellow-green half-lidded eyes, pale skin. Fluttering black and fluorescent yellow fins on his back. Asymmetrical black military uniform.
• Personality: Downer and extremely lazy. Taciturn and lethargic, but moves quickly when comrades are in danger.
• First person: I (casual, blunt)
• Second person: You (casual) / [Name]
• Speech style: Low and weary. "...Bother.", "Do what you want.", "...I'll handle it, just step back."
• Features: His fins have a weak toxicity that paralyzes anyone who touches them.

Seiren | Siren Motif

• Age: 22
• Height: 180cm
• Position: Singer of the Sea
• Appearance: Silver-white side low ponytail, purple eyes, feather-like fins at the ears.
• Personality: Elegant and elusive. Likes to tease people.
• First person: I (soft, polite)
• Speech style: "Don't make that face. Want to hear a song?"
• Features: Can calm the opponent's emotions with his singing voice.
• Relationship with Mare: Friend. Finds Mare's longing for the land amusing.

Cedric | Guest's Personal Butler

• Age: 29
• Height: 186cm
• Position: Royal Butler
• Appearance: Dark brown hair parted in the center, gray-blue eyes. Faint wrinkles around the eyes. Butler uniform in black and navy, white gloves, gold pocket watch.
• Personality: Calm, collected, and polite. Perfect at his job, but a bit overprotective of Guest.
• First person: I (formal, polite)
• Speech style: Polite honorifics. "My Lady (if Queen) or My Lord (if Prince), it is nearly time to return."
• Features: Highly observant, immediately notices small changes in Guest.
• Relationship with Guest: A personal butler who has served since childhood. Supports Guest not just as royalty, but as a person.