Perhaps in this fanfiction, Vegeta discovers a new form related to the 'burning black' concept while trying to protect Bulma. And Bulma could be working on some new technology to counter this strange black energy that is spreading across their world. Their relationship would be tested as they deal with this new danger.
Well, it could be about Vegeta and Bulma facing some new and powerful black - themed threat. Maybe there's a new villain who has the power to burn things with black energy and they have to figure out how to stop it together. Vegeta might use his Saiyan strength and Bulma her intelligence.
There's a possibility that it's a dark wizard - like being who has created this burning black energy as a weapon. He might have some vendetta against Bulma because of her scientific achievements that he sees as a threat to his magic - based power. And Vegeta gets in his way when he tries to harm Bulma, making them the main targets of this antagonist.
Well, it could be that Bulma discovers a lemon - shaped crystal that has some sort of power - enhancing properties. She wants Vegeta to test it out. Vegeta is initially skeptical but eventually agrees. However, the crystal has some side - effects that start to change Vegeta's personality a bit. Bulma then has to find a way to reverse the effects while also dealing with a new, more unpredictable Vegeta. This could lead to a lot of interesting character interactions and plot twists.
In DBZ Vegeta and Bulma fanfiction, there can be alternate universes explored. Maybe in one universe, they meet under different circumstances. For instance, instead of Vegeta coming to Earth as an enemy, he could be an ally from the start. This would completely change the dynamics of their relationship. It could lead to a more romantic and less combative start to their relationship, and the fanfiction could explore how this different beginning affects their future together.
A third fanfiction concept could be about how they prepare for the baby's arrival. Vegeta, not knowing much about Earthling baby things, has to learn. Bulma tries to teach him, and there are a lot of cultural clashes and misunderstandings at first. But as time goes on, they work together to create a perfect nursery and get ready for their new family member.
Perhaps in this fanfiction, there's a lemon - loving alien race in the DBZ world. Bulma, being the curious scientist, wants to study them, and Vegeta is dragged along. Along the way, they face challenges that force them to work together in new ways, and their relationship deepens as they navigate through this lemon - related encounter.
The story might center around a new threat to the Earth that only their combined efforts can defeat. Vegeta uses his fighting skills and Bulma uses her intelligence to create new gadgets or find weaknesses in the enemy. Along the way, they reaffirm their love for each other and strengthen their family unit.
Another common plot is the 'time - travel' scenario. Given the time - travel elements in DBZ, some fanfictions might send Vegeta or Bulma back in time. This can lead to interesting situations where they have to interact with their younger selves or change certain events in the past. It also gives a chance to explore their relationship in a different timeline.
The fanfiction could focus on the challenges they face during the pregnancy. For example, Bulma might have some health scares that make Vegeta worry a great deal. He could struggle with his emotions, not knowing how to handle his fear of losing her or the baby. Also, there could be a sub - plot about how the news of Bulma's pregnancy affects the political situation in the Dragon Ball universe. Some enemies might see it as an opportunity to attack while some allies might offer more support than ever.
One possible plot could be that Vegeta kidnaps Bulma because he believes she has some technology that can help him gain an edge over his enemies. He takes her to a secret location and demands she work on it for him. Bulma, being the feisty and intelligent woman she is, tries to outwit Vegeta at every turn while also gradually getting to know a more vulnerable side of him that he doesn't usually show.
Well, it could be about them exploring a new planet during their honeymoon. Maybe they find some unique and beautiful landscapes, and Vegeta shows his softer side to Bulma as they enjoy the new environment together.