The theme of redemption can't be ignored. Since they are given a second chance in the form of being reborn, they might strive to atone for their past sins. And there's also the theme of survival, as they navigate a world full of enemies who might be after them for their past deeds or new - found power.
Well, power and its corrupting influence can be a theme. As the assassin gains new abilities in the reborn state, they may face the temptation to use it for wrong reasons. Also, loyalty is a theme, whether it's loyalty to an old cause or to new allies they make along the way.
One possible theme could be identity. The young lord has to figure out who he is now as an assassin compared to his former self. Another theme might be redemption. Maybe he's trying to atone for something in his past life through his new assassin role.
One of the main themes is probably pride itself. The characters might struggle with their own pride, whether it's a noble's pride or a sense of self - worth. Another could be about power and how characters use it in the context of the story's world.
Another theme could be redemption. The assassin, having done bad things in the past, might be seeking to atone for his sins through his new life as a farmer. He could be trying to make up for his previous actions by living a more virtuous life, growing crops and helping the local community. This theme of transformation from a 'bad' person to a 'good' one is quite common in such light novels.
Another theme is power and how to use it. In these novels, the assassin usually has some skills from their past life. They need to decide how to use those skills in the new world, whether for good or bad. For example, in 'The World's Finest Assassin Gets Reincarnated in Another World as an Aristocrat', the main character has to balance his assassin skills with his new aristocratic identity. It's a complex exploration of power dynamics.
One of the main themes could be redemption. Since the dragon is reborn, it might have a chance to right the wrongs of its past. Another theme might be power and how it is used or misused. The reborn dragon may have great power and has to decide how to wield it.
Another theme might be power and its consequences. As an assassin, he has a certain kind of power. The novel could explore how this power affects him and those around him. For instance, does it isolate him or attract unwanted attention?
One of the main themes is redemption. The assassin has to come to terms with his past actions. Another is power and how it can be used or misused.
One of the main themes is self - discovery. The protagonist, being reborn, has to figure out their new identity and purpose in this space mercenary world. Another theme is survival, as the life of a mercenary is full of dangers.
One of the main themes could be adaptation. The protagonist being reborn as a vending machine has to adapt to a completely new form and existence. Another theme might be the exploration of the world from a non - human perspective. Since it's a vending machine, it experiences the world in a very different way than a human would.
One main theme could be redemption. Since the demon king is reborn, he might be seeking to atone for his past sins or mistakes. Another theme could be power struggle. Even as a reborn entity, he may still have to fight for his place in the new world.