The concept of immortality might also be a theme. The vampire's immortality in 'Contract with a Vampire' light novel can contrast with the mortal human characters. This can lead to themes of envy, the passage of time, and the different ways the characters view life and death.
One main theme is probably the relationship between humans and vampires. It often explores how they interact, whether it's a power struggle or a more complex emotional connection.
Another theme could be friendship or alliance. Since they have a contract, they are bound in some way, and through this connection, themes of loyalty, trust, and building a relationship despite their differences are likely to be explored. For example, they might have to rely on each other in a world full of challenges and enemies. Also, the idea of acceptance of the other's 'monstrous' or different nature could be a theme as well.
One possible main theme could be the struggle between the vampire nature and human emotions. Vampires often have to deal with their inhumane instincts while still having some remnants of human feelings, especially if the character Michaela has a complex backstory related to her transformation into a vampire.
The search for identity is often a theme in vampire stories. Mikaela might be on a journey to discover who he really is as a vampire. Is he a monster? Or is there more to him? This self - exploration can be a driving force in the story, especially as vampires are often depicted as being different from humans yet having some connection to them.
Love and loyalty are also prevalent. Sometimes, the blood contract is made out of love or loyalty, and the story then unfolds around how the characters uphold or break this bond. For example, a character might sacrifice a lot to keep the terms of the blood contract because of their love for someone else. It adds a layer of emotional depth to the story.
One of the main themes is the battle between good and evil. D, as a vampire hunter, constantly faces off against the forces of darkness. Another theme is the exploration of the nature of vampires. The novels often delve into what makes a vampire, their powers, and their place in the world. Also, there's a theme of loneliness as D, being a dhampir (half - vampire, half - human), doesn't fully belong to either the human or vampire world.
One main theme is isolation. Since the character is a hikikomori, the sense of being alone and separated from society is often explored. Another theme is the duality of the vampire nature. As a vampire princess, she has to deal with her predatory instincts while also having some form of humanity or moral compass. And there's often the theme of the unknown and the supernatural, as the vampire world is full of mystery.
The themes include sacrifice and redemption. The protagonist may have to sacrifice something in order to make the contract with the demon king, and throughout the story, there could be a journey towards redemption. Also, there is the theme of trust. Since the demon king is not a typical ally, the relationship between the protagonist and the demon king is built on a very fragile trust, which is constantly tested.
A common theme is the power and responsibility that comes with soul contracts. Characters often have to deal with the consequences of making these contracts, whether it's gaining new powers or facing unforeseen challenges.
Love and sacrifice are main themes. The love between the characters is complex and often involves sacrificing for each other or for a greater cause in the world of Vampire Knight novel.
One of the main themes is love. The complex relationships between the characters, like the love triangle among Elena, Stefan and Damon, are central. Another theme is the struggle between good and evil. Vampires in the novel constantly face the choice of giving in to their dark natures or striving for redemption. Also, the theme of mortality and immortality plays a part. Mortal characters interact with immortal vampires, which creates a lot of interesting situations and character developments.