Marron's parents are an unlikely pair; her father is the strongest human on the planet, her mother is a cyborg that was once a huge threat to Earth. Somewhere along the way he fell in love with her and she eventually fell back.
Marron is clearly very close to her family. They seem to have lived at Kame House for most if not all of her life in the series, and it's known that she doesn't enjoy flying, so it's likely that her parents are also her closest friends. Early on, Kuririn dotes on her, and though Juuhachigou is a bit sterner, her actions at the 25th Tenkaichi Budoukai indicate that she is a caring mother.
Both Kuririn and Juuhachigou appear to be fiercely protective of Marron, and it's not a far stretch to imagine that as a child and even later on she was just a tad spoiled. This hasn't been a detriment to her cheerful personality, though (excepting the point in the story when she was possessed by Bebi). Her enthusiastic support of her parents in the tournament and at other points in the story are also proof of her love for them.
One of the first characters introduced in the series, Kuririn appeared for the first time in episode 14 of Dragon Ball, and in chapter 25 of the manga. The second Dragon Ball movie is also a remake of his debut. At this point, he is thirteen years old when he appeals to Muten-Rôshi for martial arts training. After they pass a few tests, he and Goku together become Muten-Rôshi's apprentices.
Kuririn's name is born from the same pun as Marron's - "kuri" is the Japanese word for chestnut. It's generally accepted that this is a reference to his head, which Kuririn diligently shaves for the first thirtysomething years of his life, in the style of Shaolin monks. He also has a pattern of six incense burn scars on his forhead from his monastery training as a child.
Kuririn is often regarded as somewhat of a joke character, probably a result of his comedic actions combined with the unflattering dialogue supplied in the North American dubbed versions of the show. In truth, he knows his weaknesses better than anyone else, and though his sense of self-preservation is always in the background, his heart takes command when the need arises. He is without a doubt one of the most dynamic characters of the series, a powerful fighter (finishing out at the highest power level among the humans by almost double) and a loyal and true friend.
You would never guess from Juuhachigou's first appearance that she would change her ways, much less marry Kuririn and settle down. She first appears in volume 29 of the manga (13 of DBZ) as one of the ruthless villains to be faced in the Android saga. Her full name, Jinzouningen Juuhachigou (lit. Artificial Human #18) is usually shortened or simply translated to "Android 18".
In Trunks' future, Juuhachigou is one of two androids who wreak havoc upon the Earth, killing all the Z-warriors apart from Trunks himself, who escapes to the past to change the timestream. As it so happens, events proceed differently even without his intervention, and after Dr. Gero activated Juurokugo (16) and Juunanagou (17) they turned on their creator. From there the androids did as they pleased, Juuhachigou eventually being consumed by Cell after Kuririn spared her life. When Cell is destroyed, Kuririn asks Shenlong to remove the explosives that were placed in her body, as it was not within the dragon's power to completely restore her to humanity. Sometime between this point and the Great Saiyaman Saga, the two are married and have had Marron.