Perhaps there is a female lead who is a part of a resistance movement. She might have special skills or knowledge that make her crucial in the fight against the forces that want to misuse the clockwork power. She could also have a romantic sub - plot with another character in the story.
One interesting concept could be the unique world - building. Maybe it has a steampunk - like setting with clockwork mechanisms everywhere, from the city's infrastructure to the characters' gadgets. This can create a really immersive and visually appealing environment.
There could also be a heroic character, like a young inventor who is trying to oppose the chaos caused by the Clockwork Joker. This character would use their intelligence and knowledge of mechanics to outwit the Joker and save the day.
It could be that Naruto or one of his friends has some sort of encounter with the 'clockwork master'. So Naruto could be considered a main character in the sense that his actions and decisions are intertwined with the 'clockwork master'. For example, Naruto might seek the help of the 'clockwork master' to defeat a particularly difficult enemy who has an immunity to normal ninja attacks but could be vulnerable to the clockwork - based jutsu.
The rulers of the clockwork empire tend to be popular too. They have the power to make decisions about the empire's development and how the clockwork technology is used. Their characters are usually complex, as they have to balance the needs of the people, the technology, and their own desires for power. They might be portrayed as benevolent leaders or power - hungry tyrants in different fanfics.
In some clockwork stories, there could be a group of characters. For instance, a team of inventors who work together to build the ultimate clockwork creation. Or a family who inherits a strange clockwork object and has to figure out what to do with it. The characters would interact with the clockwork elements in different ways, depending on their personalities and goals.
There might be a mechanic who is responsible for maintaining the city's clockwork systems. He or she could be a central character, dealing with all the mechanical problems and perhaps uncovering secrets within the city as they work. There could also be a rebel figure who wants to break free from the strict order of the clockwork city.
The main characters include Tessa Gray. She is the central character with her unique powers. Then there are Will Herondale and Jem Carstairs. Will is a Shadowhunter, who is complex and has his own secrets. Jem is also a Shadowhunter, and he has a special bond with Will. There are other characters as well, like Charlotte Branwell, who is in charge of the London Institute of Shadowhunters.
Not having read the book, I can only speculate. The clockwork girl must be a central character. There may be other characters such as a friend or ally who stands by her side in a world that might be hostile to her. There could also be a villain who sees her as a threat or an opportunity to gain power, depending on the nature of the story.
In the novel 'A Clockwork Orange', the main characters are Alex, who undergoes a transformation throughout the story, and the people he interacts with, such as the prison chaplain and the doctors trying to 'cure' him of his violent tendencies.
As I don't know the specific 'clockwork original story', I can't say for sure who the main characters are. It could be an inventor who creates the clockwork devices.