The main character is Obito without a doubt. The other main character in the 'obito love story' could be a character from a different clan. Their different backgrounds would add more depth to the story. For instance, if Obito is from the Uchiha clan and the love interest is from the Hyuga clan, their relationship would be full of cultural and clan - related tensions, making their love story all the more interesting.
Besides Obito, Sasuke could be a main character in this fanfiction. Sasuke, with his own journey of redemption and his understanding of power and the ninja world, could have an interesting dynamic with the reincarnated Obito. Also, Sakura might play a role. She could be the one who tries to heal the reincarnated Obito, both physically if he is injured during his new adventures and emotionally from the traumas of his past life.
The person Obito Uchiha was in love with was Rin. She was an important part of his life growing up in the Hidden Leaf Village. They had a connection that was rooted in their shared experiences as ninja trainees.
Obviously, Obito is one of the main characters. He has a complex backstory and his presence is bound to have a big impact on the Akatsuki.
There could also be interactions with the new generation of ninjas. They might view Obito as a sort of legend or a cautionary tale. Their fresh perspectives could either inspire Obito to change further or make him feel even more out of place in this new post - war ninja world.
Based on the title, it seems that Obito no Hime (the princess) and Kubinashi Kishi (the knight) are likely to be the main characters.
Well, without more context, it could be anyone. It might be a young couple from different social classes, like Romeo and Juliet.
Obito had a deep love for Rin. He always cared about her and tried to protect her. His love was pure and strong. However, their story was filled with tragedy. Rin's death was a great blow to Obito and changed him in many ways.
Minato might also be a prominent character. As their teacher, he can influence the way Obito and Kakashi interact. In some fan fictions, he could be the one to help them resolve their differences or provide some crucial information about their past that changes their current situation.
Since we don't have much information about the '1960 love story', it's hard to say who the main characters are. They could be ordinary people, like a factory worker and a schoolteacher.
I'm not sure as the title doesn't give away the main characters directly. But it could be a couple who are caught up in the events of 1984 while experiencing love.