Dagon

Dagon is an aquatic monster of the northern seas. She often poses as a mermaid to trick careless men and sucks them dry.

On his way to meet Poseidoness, Dagon attacks Luka. She disguises herself as a mermaid before revealing her true form.

Encyclopedia Entry
"A monster that lives in the Northern Sea. Posing as a mermaid, she catches careless men who dare to get too close to her. Her mimicry isn't that great, but due to the obfuscation of the sea water, some men have been known to be tricked. In addition, due to living so close to the northern continent, she is quite a powerful monster.

''Once she catches a man, she uses her lower body to wrap around him, squeezing out his semen. An overly happy, innocent monster, she has been known to squeeze men to death with a carefree smile on her face."''

Battle Overview
Disguised as what appears to be a harmless mermaid, she says to have a present and asks Luka to near. If he chooses "Approach", she'll reveal her true form and put him in an bind; without Gnome, the restriction is unbreakable and he falls mercy to her.

If he does not approach, she reveals her true form and decides to take him by force. She often aimlessly swims around, as all her attacks are only bound ones. Using the Undine + Serene Demon Sword combination, she falls easily.

Succumbing to pleasure, she continues squeezing Luka's penis with her tentacles until he is sucked dry, resulting his death.