In a fanfiction where Majin Boo invades the Naruto universe, the first thing that might happen is that there would be mass panic. Majin Boo's appearance would be something out of the ordinary for the Naruto characters. The Kages would have to quickly assemble and come up with a plan. They might try to use sealing jutsus which are common in the Naruto world. However, Majin Boo's resistance to such things in his own universe might make it difficult. The characters like Rock Lee, who rely on physical combat, would find it tough as Majin Boo can take a lot of punishment. And the story could also explore how the different chakra natures interact with Majin Boo's magic - like powers.
Well, if Frieza invaded the Naruto universe in fanfiction, it would be a total chaos. Frieza is extremely powerful with his ability to transform and his deadly energy attacks. The ninjas in the Naruto world would be in for a huge shock. They've never faced an enemy like him before. Naruto and his friends would have to quickly figure out Frieza's weaknesses. Maybe they'd try to use their jutsu in creative ways, like using shadow clones to confuse Frieza while they search for a way to defeat him. But it wouldn't be easy as Frieza is not someone to be underestimated.
One way could be for Naruto to use his Sage Mode combined with the power of all the tailed beasts. This super - powered form might be able to match Majin Boo's strength. Also, Sasuke with his Rinnegan could try to use some space - time ninjutsu to trap Majin Boo. And the rest of the shinobi could support them with their various jutsus. For example, the Nara clan's shadow techniques could be used to hold Majin Boo in place while Naruto and Sasuke attack.
Maybe in the fanfic, Majin Boo has done something extremely unforgivable to Bulma, like harming her family or friends. This could be the reason for her inability to forgive.
From the search results provided, there was no mention of dark novels where the protagonist invaded the universe. I don't know the answer to this question.
I'm sorry, I haven't read a specific 'bulma wintt forgive majin boo fanfic' so I can't recommend one directly. You could try searching on fanfic websites like FanFiction.net or Archive of Our Own.
One possible plot could be that Majin Boo has done something really bad that affects Bulma. But then, through a series of events, like Majin Boo saving Bulma's life or showing remorse in a very genuine way, Bulma begins to consider forgiveness. Maybe Majin Boo has to sacrifice something important to prove his change of heart, and in the end, Bulma fully forgives him.
It could also be due to the general nature of Majin Boo. He was initially a villain created for evil purposes. His appearance and the way he carried out his actions were often grotesque and malevolent. Bulma, who is used to a more civilized and scientific environment, might be repulsed by his very existence and find it unforgivable that he was able to cause so much trouble in their world.
One possible fanfiction could involve Naruto being transported to the Dragon Ball universe where he meets Female Majin Buu. Maybe they start as adversaries at first. Naruto, with his ninja skills, tries to fight her. But then they realize they have some common ground in their love for food. And they could end up teaming up against a greater threat in the Dragon Ball world.
Naruto himself is often a central and popular character. Since it's a Naruto - related fanfiction, his presence is expected. Sasuke is also likely to be popular as he is one of the main characters in the original Naruto series. And any new majin - created characters can also gain popularity if they have interesting backstories and powers.