Dantalian no Shoka Wiki
Sea creature

Japanese Name


Romanized Name



Lass (小娘 Komusume)


Chapter 3 (light novel 6)

Voice actor




Lecia is a sea devil adopted by John McGuigan. She uses a copy of the Book of Humanization to live among humans. She’s part of the Book of Humanization story.


Fifteen years before the main event of Book of Humanization, the military buried metallic tanks filled with poison gas on the Latham Archipelago. One night, the chemical weapons leaked into the water, killing most of the local sea devils. McGuigan found Lecia, the only survivor, embraced by her dead mother. Lecia had been lucky, since she was separated from her mother when the tragedy occurred. McGuigan adopted Lecia, acting as if she’s a niece who lost her parents.

Under McGuigan’s castle, a natural cave connected to the sea is used as Lecia’s room. McGuigan eventually gave her a copy of the Book of Humanization so that she could disguise herself and live among humans. A few days before the main events of Book of Humanization, McGuigan planned to kill the partners of his late father, men who were about to deal with the military, allowing the disposal of chemical weapons in the region once again. McGuigan sent for Hugh and Dalian, so they can take care of Lecia in case something bad happens.

Sea devils[]

Lecia, Lucrece and probably Bonnie are all sea devils (海魔 Umi Ma). According to McGuigan, sea devils look frightening to people, but they are kind creatures. They used to visit the Latham Archipelago every few years to make children, rarely making contact with people. The local old fishermen know about the sea devils’ true nature, while other people spread unfounded rumors about how the creatures used to attack ships and steal its valuables. It’s said that they live among the rocks around the island, luring men and eating them. Fishermen avoid those waters. It’s rumored that McGuigan’s father and other four men became rich by killing them and taking their treasure. In fact, their fortune came from the military, which in exchange were allowed to bury chemical weapons on the island.

Instead of legs, sea devils have long fish tails covered with silver scales, with a large translucent fin, like the ones from sharks. Thick translucent tentacles grow from their backs, each one ending in a mouth with sharp teeth. Other than that, they look like humans. They live in seas and oceans all over the planet, although many use copies of the Book of Humanization to live among humans. They have incredible strength. They can emit a high-frequency sound scream which shakes windows and bothers the human ear. The tentacles may be used to restrain a man, or to choke him to death.[1]

Sea devils do not bury their deceased. In the past, when they wished to remember the departed, they visited the Holy Land of the Sea Devils (海魔の聖地 Umi Ma no Seichi), a cave located in a small rocky island not far from the main island of the Latham Archipelago. It's a place of difficult access due to dangerous currents and rocks. The uninhabited island is five kilometers in diameter, has high sheer cliffs and no trees or bird nests. The sea devils would go to the Holy Land to use the Book of Paradise and relive the happy memories with those who died. However, sea devils stopped visiting their ancestors, so the Phantom Book got out of control and started to attract innocent people to use them as power source. The Sea Devil Queen became its user.[2]


She’s a shy and frightened girl. She and Dalian are alike, in the way they love books and hide behind their protectors while meeting a stranger. Lecia protects her copy of the Book of Humanization as if it’s very valuable to her. The gentle girl doesn’t speak. She uses chalk and the small blackboard hanging from her neck to communicate. She quickly befriends Dalian, ignoring the Biblioprincess’ bad manners. Lecia enjoys the scent of the sea. She’s not very expressive. She kindly presents McGuigan with a simple but beautiful necklace made of rope, pebbles and seashells, of her own making. She worries about him.[1]


Disguised as a human, she’s no taller than 1.4 meters. Her meekly personality makes her look younger than Dalian. She has gray, long hair, some of which is tied into two tails. A small blackboard hangs from her neck, which she uses to communicate.[1]


McGuigan hears Lecia’s cry. He finds her on the beach, surrounded by the corpses of other sea devils. She’s being embraced by her dead mother.

Before reaching the Latham Archipelago, Hugh and Dalian learn from the captain of the ship that the place is surrounded by underwater rocks. It’s rumored that sea devils live among those rocks, luring men in order to eat them. Some frightened fishermen even keep their distance from that region. Dalian ends up falling overboard. Later, at the port, the body of Mr. Smythe is carried away from his ship. His head was removed, as if it was bitten off by a monster.

McGuigan takes Hugh and Dalian to his castle, where he introduces Lecia. The latter hides behind McGuigan to timidly examine the guests. Hugh notices a book in her hands. According to McGuigan, he adopted his niece after the death of her parents. Rather than speak, she writes on a blackboard to communicate. McGuigan had sent for Hugh and Dalian because he wants Lecia to make friends. He knows that Dalian also loves to read. However, the Biblioprincess refuses to befriend her. After all, Dalian doesn’t like children. As retribution for the rude comment, Lecia mentions Dalian’s height, making her furious. Lecia affirms that she had read the book on Dalian’s hands. Since Dalian is doubtful, Lecia reveals the ending. Lecia ignores her anger. Lecia pulls Dalian by the hair. Dalian would be taken to bathe and to change clothes. Lecia enjoys the smell of the sea on Dalian’s hair.

Dalian change clothes

Dalian borrows Lecia's clothes.

It began to dark when Lecia and Dalian returned to McGuigan’s study. Dalian had borrowed Lecia’s clothes. The Biblioprincess is almost looking like an ordinary girl. Although Lecia is inexpressive, McGuigan knows that she’s happy with Dalian’s presence. An old butler appears to inform McGuigan about policemen wishing to make some questions about Mr. Smythe’s death. Lecia hides behind McGuigan. The latter leaves the study for a moment to welcome the policemen. Lecia takes beautiful pebbles and seashells from a small box. She begins to use a rope to join them. Hugh asks if McGuigan has a book about sea devils. Lecia’s eyes widen for a moment. She shakes her head. Soon after, Hugh notices an old book in McGuigan’s bookshelf. Before he can check it, Lecia grabs the book and runs away, looking very scared.

The next morning, Lecia guides Hugh and Dalian around the island. Dalian comes along, apparently because she didn’t want to let Hugh and Lecia alone. The girls read enthusiastically on the backseat. McGuigan had informed Hugh that Bentley was also killed, supposedly by sea devils. That’s why Hugh decided to investigate.

Next to the port, Lucrece shares more information. It’s said that, fifteen years ago, Smythe, Bentley, Vernon, Haycroft and McGuigan’s father made fortune after killing the sea devils and stealing their treasure. It seems like the monsters are after revenge. Lecia becomes worried about McGuigan, since he may become the next victim. As a biologist, Lucrece affirms that she won't be surprised if sea people lived hidden somewhere, although probably not around the Latham Archipelago. Lecia gasps loudly. She notices a sailor with bloody clothes inside a lifeboat. According to a fisherman, Vernon was trying to leave the island, but his ship sunk.

Hugh, Dalian and Lecia return to the castle. Lecia goes to her room. McGuigan knows that he’s in danger. Perhaps that's why he sent for Hugh and Dalian. Lecia should be taken care of if something bad happens. When men hired by Haycroft storm the castle, McGuigan tells Hugh to take Lecia and run away. Hugh and Dalian enter Lecia’s room. Curiously, it’s a natural cave connected to the sea. They see Lecia soaked wet, the old book in her hands. Hugh tells Lecia that they should leave. Lecia tries to go after McGuigan, but she’s stopped by Hugh. An explosion shakes the entire castle. Lecia drops the book. The attackers enter the cave and start to shoot. Lecia extends her arm to grab the book, but it’s destroyed by a bullet. Suddenly, Lecia becomes a sea devil. The attackers become scared. After unloading their guns, they throw grenades at the trio. Lecia throws Hugh and Dalian into the water, showing inhuman strength. Lecia is buried by blocks of stones.

Lucrece was outside, so she witnessed Lecia being kidnapped by the men. Lecia had bruises, but she was alive. Hugh, Dalian and Lucrece return to the castle. McGuigan explains that Lecia was using the Book of Humanization to live among humans. According to him, sea devils are kind creatures who used to visit the island every few years to make children. They died when metal tanks buried by the military leaked poison gas into the water. Lecia was separated from her mother on that occasion, so she was the only survivor. Now, Haycroft wants to use Lecia to publicly announce that sea devils are responsible for the deaths of Smythe, Bentley and Vernon. McGuigan flies off on his seaplane to save Lecia.

Hugh and Dalian also go to Haycroft’s house. They find Lecia as a hostage, tied with chains, at Haycroft’s feet. McGuigan is bleeding on the floor. Haycroft plans to deal with the military once again. History will repeat itself. Veteran soldiers surround Hugh and Dalian. Haycroft threatens to kill McGuigan. There’s a high-frequency sound which shakes the windows. Lecia lets out the same cry. Haycroft steps on her head, trying to make her stop. Haycroft and his soldiers are restrained by translucent tentacles. A tentacle easily breaks Haycroft’s arm. Sea devils enter the room through windows and ventilation shafts. Lucrece appears, revealing herself as a sea devil. Unable to breath, Haycroft dies.

At the beach, Lucrece explains that sea devils live in seas and oceans all over the world. Some live among humans, disguised. McGuigan entrusts Lucrece with Lecia. Now that her copy of the Book of Humanization is destroyed, Lecia can't live with McGuigan. She’s decided to live in the sea. McGuigan strokes Lecia’s head one last time. Lecia gives him a beautiful necklace she made with rope, pebbles and seashells. Before Lecia can leave, Dalian gives her the original Book of Humanization. Lecia will be able to return to land if she wishes. Lecia uses her finger to write “see you again” on Dalian’s palm. Lecia and Lucrece swim away.[1]


  • McGuigan explains that sea devils were probably mistaken by sea-gods in the past.[1] He mentions Neptune from Roman religion, Glaucus from Greek mythology, Njörðr from Norse mythology, and Manannán mac Lir from Irish mythology, all figures associated with the sea.[3][4][5][6]
  • Lecia is a mute sea devil who disguises herself as a human.[1] Similarly, the Little Mermaid gave away her voice to become a human.[7]
  • Sea devils are like mermaids, aquatic creatures with the head and upper body of a female human and the tail of a fish. In some traditions, mermaids can be benevolent or beneficent, while in others they lure men to their deaths.[8]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 The Mystic Archives of Dantalian light novel, Chapter 3, light novel 6.
  2. The Mystic Archives of Dantalian light novel, Chapter 4, light novel 6.
  3. Neptune (mythology). (2020, June 6). In Wikipedia, The Free Encyclopedia. Retrieved 23:55, June 18, 2020, from https://en.wikipedia.org/w/index.php?title=Neptune_(mythology)&oldid=961100143
  4. Glaucus. (2020, April 8). In Wikipedia, The Free Encyclopedia. Retrieved 23:55, June 18, 2020, from https://en.wikipedia.org/w/index.php?title=Glaucus&oldid=949804400
  5. Njörðr. (2020, June 9). In Wikipedia, The Free Encyclopedia. Retrieved 00:05, June 19, 2020, from https://en.wikipedia.org/w/index.php?title=Nj%C3%B6r%C3%B0r&oldid=961579424
  6. Manannán mac Lir. (2020, June 16). In Wikipedia, The Free Encyclopedia. Retrieved 23:57, June 18, 2020, from https://en.wikipedia.org/w/index.php?title=Manann%C3%A1n_mac_Lir&oldid=962827797
  7. The Little Mermaid. (2020, June 18). In Wikipedia, The Free Encyclopedia. Retrieved 23:00, June 20, 2020, from https://en.wikipedia.org/w/index.php?title=The_Little_Mermaid&oldid=963262357
  8. Mermaid. (2020, May 29). In Wikipedia, The Free Encyclopedia. Retrieved 23:24, June 20, 2020, from https://en.wikipedia.org/w/index.php?title=Mermaid&oldid=959645605


Dalian - Flamberge - Rasiel


Hugh Anthony Disward - Hal Kamhout - Professor

Recurring characters

The Girl in the Bookshelf - Wesley Disward - Kamilla Sauer Keynes - Jessica Elphinstone - Shura Irmania - Armand Jeremiah - The Perennial Wisdom's Owner - Oliver Grosseteste - Mithril - Hugh's mother - Hugh's father - Natalia - Hal's beloved - Miss Roedean

Creatures and machines

Atlantic Rim - Automaton - Beast of Ashwell - Book of Royal Power - Branches of Relationship - Broken Wings - Dantalian - Dead Book - Ghost train - Golem - Guignols - Guillemot - Heath - House-elf - Kasuruhau - Logbook - Loge's giant - Musical automaton - Pioneer Plant - The Harlequinade's creatures - Ras Alhague monster - Scarlet Robe - Sea devils - Steam Giant - The Queen of the Night - W Machine - Winged women - Wooden dolls - Zombies

Dalian Days

Priscilla Riley - Cecil Patreina - Margaret Manschwell


Male Characters - Female Characters
Phantom Book Users - Deceased Characters