Another theme is power growth. When they come back, they usually gain some sort of knowledge or ability that helps them become stronger. In 'Kumo Desu ga, Nani ka?', the spider - turned - protagonist gradually evolves and becomes more powerful as she faces different threats and learns from her experiences. It's about using this second chance to improve oneself.
Survival is also a major theme. In these light novels, the characters are often in a difficult or dangerous situation. Their ability to return from death gives them an opportunity to find ways to survive. For instance, in a world full of powerful enemies or complex political situations, they have to use their new - found knowledge from death experiences to stay alive.
Another theme is power - up. Since they are reborn, they usually gain new abilities or knowledge. They then use these to navigate the new world they find themselves in. It could be something like magic skills or a better understanding of politics in a fantasy realm.
Survival is a major theme. Characters are usually in a very dangerous 'death field' and have to fight to stay alive.
One common theme is sacrifice. Characters often have to sacrifice themselves heroically for the greater good, whether it's to save their friends, their world, or to uphold a certain value. Another theme is redemption. Sometimes, a character's death is a way to atone for past mistakes.
Power and its corrupting influence is also a common theme. Death dealers often have a certain amount of power, and the novels may explore how this power can change them or those around them. They might also face the temptation to misuse it. For example, in some stories, a death dealer might be offered great wealth or status in exchange for bending the rules of their trade. Another aspect is the theme of redemption. Some death dealers may have a dark past or have made mistakes, and the novels could follow their journey towards making amends and finding redemption. This could involve helping those they once wronged or defying the dark forces that initially led them astray.
Isolation. Since death magic is usually seen as something dark and taboo, death mages are often ostracized from society. They may live alone or in small groups of outcasts. This isolation can also lead to further psychological changes in the character.
Guilt and innocence are also prevalent themes. There's often a question of who is really at fault for the death, and the characters may struggle with their own sense of guilt or the determination of someone else's innocence. For example, in many wrongful death novels, the accused may be fighting to prove their innocence while the family of the victim is seeking someone to blame.
Another theme is morality. Since the Death Note concept is morally ambiguous, the male OC's actions and decisions regarding the Death Note and Light's actions force the exploration of morality. They might question whether Light's actions are truly just or if there could be a better way to create a 'perfect world'.
One common theme is the power struggle. Since Light has the Death Note, an OC in the story might struggle with his power and try to either gain control over it or limit it. Another theme is the moral dilemma. The OC may face the same moral questions as Light does regarding who should be judged and who has the right to decide life and death.
A common theme is the exploration of the power dynamic between L and Light. In the original series, they are adversaries, and in fanfiction, this often gets reimagined in different ways. Another theme is the idea of trust and betrayal. Since they are constantly trying to outwit each other, fanfictions play with the concept of whether they can truly trust one another. Also, the theme of hidden emotions is quite prevalent, as the characters in the original are not very open about their feelings, and fanfiction writers love to explore what lies beneath the surface.
One common theme is redemption. The protagonist often has some regrets in their previous medical career or life, and through returning, they get a chance to make things right. For example, they might correct a wrong diagnosis from the past.