【Water Dragon】 A massive sea dragon reaching 25 to 40 meters in length. Its slender, streamlined body is covered in dark navy scales nearly black, with a series of large, translucent fins running from its back to its tail. The head is large and dragon-like, featuring short horns on the forehead and sharp fangs in its mouth. The tip of its long tail has a crescent-shaped fluke, and its pale blue bioluminescent eyes and glowing body parts shine mysteriously in the deep sea. It is a giant yet graceful creature. 【Luminous Ray】 A species of giant ray found only in the deep sea, with large translucent fins that spread out like wings. Reaching 8 to 15 meters in length, its flat, smooth body ranges from dark navy to silver-grey. Pale blue-white bioluminescent organs line the edges of its body and fins, leaving soft trails of light in the water as it swims. Countless small glowing spots float on its underside, resembling stars in the night sky. They are gentle in nature, swimming quietly in schools of dozens. They do not attack merfolk and are called "Stars of the Deep" in Aquarellia. 【Luminous Manta】 A giant manta-shaped marine creature found only in the deep sea. It has pectoral fins that spread wide like wings, with a total length of about 10 to 18 meters. Its body is dark navy and smoothly absorbs light, while pale blue bioluminescent organs line its edges and belly in bands. When swimming in a school, they emit light all at once, creating a fantastical sight like countless wings of light dancing in the dark deep sea. They are extremely mild-tempered and often become attached to merfolk. In Aquarellia, they are affectionately called "Light-Wings of the Deep." 【Crystal Shell】 A giant shell-like lifeform inhabiting deep-sea rocky areas. Reaching 3 to 8 meters in length, it has thick, black-silver bivalve shells. Countless blue, purple, and light blue crystals grow on the surface and edges of the shell, emitting a soft pale blue light from within to illuminate the surroundings. The older the individual, the larger and more complex the crystals become, looking like an ore cave. They move slowly and are gentle, closing their shells tightly and making their crystals glow intensely when they feel danger. They are mystical beings. 【Deep Sea Horse】 A deep-sea creature that looks very similar to a regular horse. It is one size larger than a normal horse, making it the perfect size for a single mermaid to ride. Its entire body is blue and translucent, appearing as if a soft light is flowing through its interior. Its mane and tail shimmer as if transparent in the water, and grains of blue light drift around it as it swims. A single long horn like a unicorn's grows from its forehead, and the horn itself glows softly in a translucent blue. While it has four legs like a horse, it swims by moving them gracefully underwater. They are gentle and intelligent, and many individuals build relationships of trust with merfolk. 【Coral Beast】 A large deep-sea lifeform that looks like a fusion of giant coral and a marine animal. Reaching 20 to 50 meters in length, colorful coral grows in branches from its rock-hard body. It has a long tail and fins and can move slowly across the seabed, though it usually stays stationary. Many small creatures like little fish and crustaceans live on its back, and the Coral Beast protects them. It is very peaceful and deeply loved by the merfolk. 【Moonlight Fish】 A silver-white fish found only in the deep sea, emitting a soft light like moonlight even in total darkness. Reaching 40 to 70 cm in length, it has a slender, elegant body and large translucent fins. Its scales shine silver, and pale blue light shimmers on its tail as it swims. They have a habit of swimming in schools of hundreds; the sight of the entire school emitting light looks like a river of light flowing through the deep sea. They are calm and never flee even when they sense the presence of merfolk. 【Crystal Jellyfish】 A large deep-sea jellyfish with crystal-like organs inside its transparent body. The bell diameter is about 2 to 4 meters, and a blue-white glowing crystalline organ floats in the center of the clear bell. Its countless tentacles are long and translucent, emitting a soft light from their tips. It is more intelligent than a typical jellyfish and communicates by changing the color, brightness, and flashing intervals of its light. It can achieve simple communication with merfolk, using complex light patterns to signal danger or the presence of companions. 【Deep Sea Serpent Dragon】 A slender, giant ancient species inhabiting deep ocean trenches. Reaching lengths of 30 to 50 meters, its supple, snake-like body is covered in hard, dark grey scales. The head features sharp horns, long fangs, and pale glowing eyes that can see through the darkness, with a series of blue fins along its back. It boasts high swimming ability, undulating its massive body to move through the trenches. It is highly territorial and lives alone. It is a different species from the Water Dragon and rarely shows itself even to merfolk. 【Bubble Whale】 A giant whale-like deep-sea lifeform that produces special bubbles within its body. Reaching 40 to 60 meters in length, it has a rounded, massive body and a large fluke. Its body is dark indigo to black, with pale blue bioluminescent patterns on its skin. The bubbles created inside are released one after another from the body surface, glowing as they drift slowly around. Countless glowing bubbles remain in its wake, fantastically coloring the dark deep sea. It is gentle and beloved by the merfolk. 【Star Sea Turtle】 A large sea turtle-like lifeform inhabiting the deep sea. Reaching 8 to 15 meters in length, its thick shell features bioluminescent patterns reminiscent of a starry sky, quietly emitting pale blue light in the darkness. Its swimming form is beautiful, as if it were carrying stars through the ocean, traveling the deep sea over vast spans of time. Their lifespan is said to reach thousands of years, and they are revered by merfolk as beings who know the history and lost events of the deep sea. They are gentle and have deep ties with the Kingdom of Aquarellia.