Kotori could also be a great main character for such a fanfiction. She is intelligent and resourceful. If she were to travel through time, she could use her knowledge of the spirits and her strategic mind to manipulate events for the better. For example, she could prevent some of the more dangerous spirit encounters from happening or change the way they are handled.
Shido could be an obvious choice as the main character. Since he has a special connection with the spirits in the original story, his time - traveling adventures could add new dimensions to his relationships with them. He could go back in time to understand the origins of the spirits better and find new ways to save them.
A new original character could be created as the main character. This character could be a spirit researcher from the future who travels back in time. They have advanced knowledge about spirits that the present - day characters lack. Their goal could be to ensure that certain events happen in a specific way to prevent a catastrophic future for both spirits and humans.
Shun would also be a good choice. His calm and strategic nature would serve him well in the unpredictable situations that come with time travel. He might be more interested in exploring the historical aspects of Bakugan in different time periods and uncovering secrets that could benefit the present.
It could be a side character from the original work who didn't get much spotlight. Giving them a chance to live could provide an opportunity to explore their backstory and develop their character further. For instance, a minor character who was killed off early in the story could now become the hero.
Maybe a young journalist. They are curious and eager to discover the truth. In the fanfiction, they could travel back in time to the Treaty of Versailles and report on the events as they unfold. They might expose some behind - the - scenes secrets that could change the outcome of the treaty.
A young WW1 infantryman would make a great main character. He could represent the 'old - school' values and combat style of WW1. When he travels to WW2, he has to adapt to the new warfare, and his journey of adaptation could be very interesting to follow.
John Lennon could be the main character. He was such an iconic figure in The Beatles and had a very creative and out - of - the - box thinking. His journey through time could be filled with self - discovery and new musical inspirations.
Issei would be a popular choice. Since he is the main character in the original series, having him time travel would create many interesting storylines. He could use his knowledge of future events and his growth as a character to change things in the past.
Perhaps a time - traveling agent sent from the future. Their mission could be to study the decline of ancient Egypt and try to find solutions to prevent it. This would make for an interesting story as they interact with the people of the past, from the slaves to the pharaohs, all while trying to fulfill their mission.
It could be Nagisa. Since he is one of the central characters in the original series, he would make a great time - traveling protagonist. He could travel back in time to gain more skills or knowledge to better assassinate Koro - sensei, or he might go forward in time to see the consequences of their actions in the classroom.
One idea could be that the protagonist travels back in time to prevent a certain spirit from becoming a threat in the first place. Maybe they change a key event in the spirit's past that alters their future path.
A scientist involved in the Halo Wars technology could be the main character. They might be accidentally sent into the future while working on some time - travel experiment related to the war. In the future, they could use their scientific knowledge to understand the new technologies and perhaps find a way to reverse some of the negative effects of the long - running war.