The antagonist is often very interesting. In Assassin Reborn, the antagonist might be someone from the assassin's past who has also changed or someone who is threatened by the assassin's new - found power. Their motives and methods of trying to stop the protagonist can be full of twists and turns, making them a character to watch out for.
As I haven't read it, I'm not sure. But it's likely that there are some unique characters. For example, there could be a person who discovers the reborn - as - underwear character and has a special reaction to it.
I think the main protagonist is often one of the most interesting characters. Their journey and development usually form the core of the story.
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.
The slime protagonist is quite interesting. His transformation from a human to a slime and his unique growth process make him stand out.
Well, the main character as the vending machine is the most interesting. But there could be other characters like the local kids who are curious about the vending machine. They might try to play tricks on it or befriend it in a way. And there could be some sort of authority figure in the town where the vending machine is located. This person might have different views on the vending machine's presence and deal with it in various ways.
Since I don't know the specific 'assassin light novel', it's hard to say. But usually, there would be the assassin as a main character, perhaps also a mentor or a target.
In this light novel, the main character, the vending machine, is full of intrigue. It has to navigate the world in a completely different way compared to its previous life. Then there are the local people in the story. Some might be curious about the vending machine, some might be greedy for the items it offers. These different types of people add color to the story. There could also be a character who befriends the vending machine in an unexpected way, which is really interesting.
There might be a mentor figure in the assassin world. This person could play a crucial role in teaching the young lord the ways of being an assassin, guiding his growth and development in this new life.
Well, obviously the reborn young lord who is an assassin is one of the main characters. He is likely to be the central figure around which the story unfolds.
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.