A really interesting fanfic idea could be set in a post - apocalyptic version of the Dragon Ball universe. Android 18 and Krillin have to fight to protect the few remaining survivors. They use their unique skills, with Android 18's android powers and Krillin's martial arts. Their relationship becomes a source of hope for those around them, as they prove that love can still exist even in the harshest of times.
One possible plot could be that Krillin discovers a new power within himself while training with Android 18. And as they train, their friendship blossoms into something more. They might have to deal with other Z - fighters being a bit skeptical about their relationship at first. But in the end, they prove that their bond is strong and they are a great team.
Krillin could be developed by showing his growth from being a bit of a coward sometimes to a more confident fighter because of his relationship with Android 18. Android 18 might be developed to show a softer side, especially towards Krillin. For example, she could start to care more about his well - being and show emotions that she previously hid.
For Krillin, he could be developed by showing his growth in confidence. Maybe he takes on bigger threats without hesitation. For Android 18, her softer side could be explored more, like her maternal instincts if they have a child.
Their relationship could grow deeper as they face the challenges of pregnancy together. Krillin might become more in tune with 18's needs, and 18 could see a new side of Krillin's caring nature.
Bulma could also be a common character paired with Krillin. Bulma is very intelligent and could potentially help Krillin figure out how to time travel better or she might be the one who creates the time - travel device in the first place. And she could use her resources to help Krillin in his time - traveling adventures.
In the manga, Krillin doesn't stop training. His sense of duty and the need to protect his comrades push him to keep improving his skills and strength.
Maybe a story where 18 and Krillin decide to open a martial arts school. They have to deal with different types of students, and it shows their relationship growing as they work towards a common goal. It can include how Krillin uses his knowledge and 18 her strength to train the students.
Well, one possible plot could be that they have a simple yet beautiful wedding on Kame House island. All their friends from the Z - fighter group come to celebrate. Krillin might be super nervous and 18 would be the calm one, reassuring him. And then they could start their life together, with Krillin teaching martial arts to local kids and 18 helping out in the community in her own unique way.
Another one is 'Love's Surprise'. Here, the krillin and 18 kiss happens in a rather unexpected situation. It's a short but really cute fanfiction that gives a new perspective on their relationship.