It could be in a very dark 'what - if' scenario where Gohan has been corrupted by some dark power and Chi - Chi, in a desperate attempt to stop him from causing greater harm, decides to take his life. But this would be a very different take on their characters, as both are generally on the side of good in the original series. It would also require a lot of build - up to make this seem remotely plausible in a fanfiction.
Maybe in a fanfiction where Chi - Chi is mind - controlled by an extremely powerful villain. The villain could manipulate her into doing such a horrible thing against her will.
I haven't come across such a fanfiction myself. It goes against the general nature of their relationship in the original series. Chi - Chi loves Gohan deeply and is very protective of him.
One reason could be a new, extremely powerful villain who targets Earth and Chi - Chi unfortunately gets in the way. Maybe this villain has a vendetta against Goku and decides to hurt him by killing his wife.
Yes, there are. Some fanfictions might depict Chi - Chi teaching Gohan important life lessons, like how to balance his human and Saiyan sides. It could also show Gohan looking up to Chi - Chi for her strength and wisdom. They might be involved in heart - warming family moments, such as celebrating holidays or dealing with the challenges that come with being part of the Z - Fighter family.
One popular theme is Gohan's growth under Chi - Chi's influence. Chi - Chi has always been strict about Gohan's education, and fanfictions might explore how this affects Gohan's development as a person and a warrior. Another theme could be family unity. Since they are an important part of the Saiyan family in 'Dragon Ball Z', fanfictions could show how they support each other during tough times.
There are various fanfictions that might explore Chi - Chi's death in Dragon Ball Z. Some might do it to explore how Goku and the other characters would react. In a sense, it could be a very dark and emotional take on the story, showing the grief and possible revenge motives of the characters left behind.
If Chi Chi gave Gohan the green light to train, it could lead to Gohan achieving higher power levels and taking on more challenging opponents. Maybe he'd even unlock new skills and transformations.
Family is a common theme. Since they have a family in the Dragon Ball series, fanfictions often explore how they raise their kids. Another theme is love, of course, showing the depth of their relationship.
Maybe in the fanfiction, Gohan could hate Videl because she's too overbearing. She's a strong - willed character and might push Gohan in ways he doesn't like.
There are many. One type of fanfiction could be about Goku and Chi - Chi's courtship. Maybe it details how Goku finally realized his feelings for Chi - Chi. Another aspect could be their cultural differences, since Goku grew up with a different set of values as a Saiyan. Fanfictions might explore how they overcome these differences in their relationship.
One unique aspect is the exploration of female relationships in the Dragon Ball world. Since most of the focus in the original is on the male fighters, fanfictions about Chi - Chi and Maron give a different perspective. For example, they can show how the two deal with the male - dominated environment.