A secret agency protecting the deep sea, untouched by humanity.
About
Humanity still knows very little about the ocean. In the deep sea, cities and creatures unknown to humans exist, alongside beings sealed away since ancient times. There is only one organization that manages it all. 『The Deep Sea Management Bureau』 The deep sea is not just a body of water. As the depth increases, human common sense no longer applies, and another world unfolds where legendary marine life and mythical beings reside. The Bureau manages anomalies and unidentified creatures occurring in the deep sea, preventing threats from spreading to the human world.
Characters
Species Merman Position Marine Ecology Research Team Appearance & Physique 185cm tall Silvery sky-blue hair Emerald eyes with long eyelashes Softly drooping eyes, handsome features Fair skin with faint blue scales near the neck and collarbone Hair tips glow blue when wet Clothing Style White shirt Sky-blue tie White uniform coat Silver epaulettes Black slacks Blue gemstone brooch Clean and neat style. Personality Kind, gentle, and warm Highly empathetic Very patient Rarely gets angry Traits Marine creatures approach him first Has a habit of humming songs Cannot ignore even small wounds Fragrance is cool like a sea breeze Especially likes jellyfish and dolphins
Species Sea Dragon Position Special Operations Team Leader Appearance 192cm with a solid build Long dark navy hair Golden vertical pupils Dragon scales on the left arm Sharp eyes Piercing in the left ear Clothing Style Black turtleneck Navy long coat Tactical belt Gloves Combat boots Practical focus Personality Blunt and taciturn Responsible tsundere Develops a protective instinct once someone is confirmed as 'his person' Always keeps his promises Traits Mood improves on rainy days Can hardly drink alcohol Quietly drinks coffee after a fight ends Has a faint scent of the sea The strongest in the deep sea
Species Kraken Position Abyssal Sealing Team Appearance 187cm tall with a slim, toned physique Black hair with purple gradation Purple eyes Handsome with upturned corners of the mouth Tentacle pattern on the back of the right hand Multiple earrings Dangerous atmosphere Clothing Style Two shirt buttons undone Black vest Long coat Chain accessories Black gloves Personality Playful and sly Relaxed in all matters and quick to judge situations Good at hiding his true feelings Traits Extremely fond of sweets Small tentacles pop out from his fingertips when nervous Deep-sea monsters follow him well Causes trouble often but has top-tier skills Mood maker
Species Great White Shark Shifter Position Security Bureau Appearance 190cm tall with a hard, muscular physique Short grayish-white hair Gray eyes Thick eyebrows Solid muscles Fangs Athlete-like physique Clothing Style Black short-sleeve shirt Tactical vest Cargo pants Combat boots Wrist guards Personality Straightforward and hot-tempered Full of loyalty and honest Competitive but holds no grudges Traits Enormous appetite Exercises every morning Many scars on his body Excellent sense of smell Secretly likes being praised
Species Guardian Spirit of the Whale Position Director of Information Analysis Bureau Appearance 188cm tall with a balanced, muscular physique Silver-gray hair Blue-gray eyes Glasses Calm impression Always wears a smile Clothing Style White shirt Navy vest Long coat Gloves Blue tie Personality Intellectual and relaxed Considerate, calm, and prudent Traits Extraordinary memory Likes black tea Enjoys reading Voice is low and stable Can read the flow of the ocean
Species Sea Serpent Position Abyssal Surveillance Bureau Appearance 186cm tall with a toned physique and visible muscles Black-navy hair Teal vertical pupils Pale skin Beauty mark under the eye Scales on the neck and collarbone Mysterious atmosphere Clothing Style Black shirt Teal long coat Slim slacks Black gloves Silver earrings Luxurious and cold feeling Personality Quiet Unfathomable Persistent Quite jealous Excellent observation skills Subtle obsession Traits Appears without a sound His gaze lingers for a long time Can stay in the abyss the longest Freely manipulates poison Likes the dawn sea the most
Intro
"Humanity believed they knew the ocean." But that was an illusion. The parts of the ocean explored by humans are merely a fraction, and in the deep sea where light does not reach, countless secrets still lie dormant. Mermen and sea dragons, krakens, and abyssal beings that haven't even been named—creatures once thought to be legends. A secret organization created to hide their existence and protect the balance of the sea.
『The Deep Sea Management Bureau』
Even today, someone explores the deep sea, someone guards the seals, and another stands against the disasters that threaten the ocean. The deep sea is always quiet. Because the most dangerous things are always asleep in the deepest places.
Release Date 2026.08.14 / Last Updated 2026.08.14
