One idea could be that Kakashi travels back to the moment right before Obito's 'death'. He uses his knowledge of future events to prevent the cave from collapsing on Obito. Then, together they are able to rescue Rin more effectively and change the whole tragic course of events.
Their relationships would become much stronger. Kakashi would no longer have to bear the guilt of Obito's 'death' and Rin's loss. Obito would be extremely grateful to Kakashi for saving his life and would likely view him as an even greater friend and ally. Rin would also be happy to have both of them by her side, and they could form a very tight - knit team.
One great Rin and Obito fanfiction is 'A Different Path'. It explores an alternate universe where Obito returns to the village earlier. The story delves deep into their relationship, showing how they might have interacted and grown together. The character development is really well - done, and it gives a fresh perspective on their bond.
The sad story of Obito and Rin is a key part of the Naruto narrative. Obito was a young ninja with big dreams and a huge crush on Rin. When Rin was seemingly killed in front of him, it shattered his world. He thought that the ninja world was full of pain and betrayal. This led him to be influenced by Madara. He became one of the main antagonists, all because of his love for Rin and the unbearable pain of losing her. His journey from a hopeful young ninja to a vengeful villain is a tragic consequence of Rin's death.
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.
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.
A good Rin and Obito fanfiction should have strong characterizations. Since we already know the basic personalities of Rin and Obito from the original story, the fanfiction should build on that and show new aspects of their characters. For example, how Obito might have changed if Rin had survived.
One idea could be a story where Female Kakashi and Obito are on a mission together in a mysterious land filled with ancient magic. They have to rely on each other's skills to survive and in the process, they start to see each other in a new light.
One great Kakashi x Obito fanfiction is 'The Bonds We Share'. It delves deep into their relationship, exploring how their past experiences shape their interactions in a post - war Konoha. It shows their growth and how they come to understand each other on a deeper level.