Some common themes include the struggle between the new sea monster self and the old human self. There's a constant internal battle of identity. Adaptation is another theme. The transformed character has to adapt to the new underwater environment, different from the human world they knew. And there can be a theme of revenge. If the transformation was due to some unjust act done to the character, they might seek revenge as a sea monster, using their new powers against those who wronged them.
Well, a frequent theme in a monster transformation story is self - discovery. As the character changes into a monster, they learn new things about themselves, like hidden strengths or fears. Then there's the theme of transformation as a punishment. It could be for a wrong they've done, and they have to endure the monster form as a consequence. And don't forget the theme of the power struggle. The monster might have to fight against other forces, either trying to control it or those who fear it.
In human into monster transformation stories, a prevalent theme is the power that comes with the transformation. Some stories show how the character gains superhuman strength or abilities as a monster but at the cost of their normal life. Another theme is the fear of the unknown. The transformation is something that is not understood by the character or those around them, leading to a sense of mystery and horror. Also, there's the theme of transformation as a form of evolution, where the character is evolving into a different form, whether it's for better or worse.
Often, it's a regular human being. Maybe a fisherman who has a strange encounter at sea and then starts to transform. Or a sailor who's been cursed.
One common theme is acceptance. The transformed monster girl often has to come to terms with her new form and find acceptance within herself. Another theme is the relationship with others, especially humans. There can be fear, misunderstanding, or in some cases, unexpected friendship or love.
One common theme is identity. The boy has to figure out who he is when he's part monster. For example, in a werewolf transformation story, he's no longer just a normal boy but has to deal with this new identity.
Well, a frequent theme is the discovery of new powers. When a hunter transforms, they often unlock abilities they didn't know they had. Also, the theme of adaptation is common. Hunters need to adapt to their new forms, whether it's physically or in terms of combat style. Additionally, the relationship with other hunters or monsters can change as a result of the transformation, which is another theme.
A common theme is growth. The slime monster often starts out small and weak and through transformation becomes stronger. For example, it might gain new physical forms or powers.
Common elements in a sea monster story include a sea monster that is powerful and difficult to defeat. This could be a giant octopus - like creature or a serpent - like being. The story might also involve a ship or sailors who encounter the sea monster. There could be a chase sequence where the sea monster pursues the ship or vice versa. And there may be elements of survival as the characters try to escape the clutches of the sea monster.
Identity crisis. The transformation makes the character question who they are. Are they still the same person inside? In 'Overlord', Momonga has to deal with his new identity as a powerful being in a game world and how that differs from his human self. He has to adapt to the moral and ethical implications of his new form and power.
One common element is the large size of the sea monster. It's usually described as being much bigger than normal sea creatures. Another is the element of mystery. People don't know much about it, like where it comes from or what it really wants. And often there's an encounter between humans and the sea monster, which creates a sense of danger and excitement.