I'm not sure specifically as I don't know which 'As Time Goes By Story' you are referring to. It could be different depending on the story.
There is no definite answer without more context about the 'As Time Goes By Story'. It could have a wide range of main characters. For instance, it could be a family with different generations, and the story could focus on how they interact and how their relationships evolve as time passes. Or it could be a single individual and the people they meet throughout their life journey.
I'm not sure specifically as I haven't read this particular novel, but generally, there could be a protagonist who is likely to be the central figure through which the story unfolds. There might also be a love interest, someone who plays an important role in the protagonist's life and their journey as time passes.
In 'Desmond goes back in time fanfiction', Desmond is surely a main character. He could meet his own family members from the past, and they could be important characters too. For instance, his great - grandfather might be a key character. There could also be a love interest for Desmond in the past, a local girl perhaps, who adds an element of romance to the story and also influences his actions and decisions while he's in the past.
There could also be characters from the past that become central to the story. For example, if they go back to the time of the First Hokage, Hashirama Senju could be a major character. Team 7 might interact with him, learn from him, or even have to work with or against him depending on the plot of the fanfiction.
A young and inexperienced member of the vanguard could also be a main character. Their naivete in dealing with the past could create interesting situations and conflicts. For example, they might accidentally change a small detail that has big consequences.
Well, while Lucy and Lula are the main characters, there could also be other supporting characters. For example, there might be Lula's family members or friends in the time period that Lucy travels to. These characters could add more depth to the story, like Lula's parents who might be initially suspicious of Lucy but then come to accept her as she helps Lula in various ways.
In 'Harry goes to Marauders time' fanfiction, Harry is the central figure. Alongside him, the Marauders are essential. James, the confident and sometimes arrogant young wizard, will be there. Sirius, the rebellious and loyal friend. Remus, the kind - hearted werewolf. And Peter, who might be on a different path in this alternate timeline. Lily, with her kind nature and powerful magic, will also be a prominent character. There could also be other Hogwarts professors from that time, like Dumbledore, who could play a role in Harry's journey in the past.
The Golden Trio, namely Harry, Hermione, and Ron. Harry is the Boy Who Lived, so his presence in the past might attract unwanted attention. Hermione is the one who probably has a plan for everything. She'd be researching how to get back to their own time and also how to not mess up the past too much. Ron is there to support his friends. He might be the one who stumbles into some unexpected situations because of his more laid - back nature, but he always manages to pull through with the help of his friends.
I'm not sure as the story isn't described in detail. But it could be an ordinary person, like a single mother trying to raise her kids while facing financial hardships, yet still managing to keep life going.
In the 'bono goes to school story', Bono is the central character. However, his parents could also be considered main characters in a sense. They are the ones who send him to school, and their influence on his school - going attitude and behavior might be part of the story. Also, any special friends he makes at school, like a best friend who he shares all his school secrets with, would be among the main characters as they contribute to the plot and Bono's experiences at school.
Since it's 'the lion goes to war story', the main character is most likely the lion itself.