Gundam Wing

Gundam Wing is an anime created by Sunrise studios. The series centers around the struggle of Earth's future colonies for independence, and its primary characters are five boys who have, by various means and for various reasons, been recruited by the colonies to pilot the giant Gundam mobile suits (basically giant robots. Kind of like the MegaZords in Power Rangers, but less plastic-y). These characters face the the horrors of war head on, and the series deals with not only the conflict itself but its impact on its main characters.

Heero Yuy
Heero (often abbreviated in fanfiction as "1") took his name from the martyred leader of colonies. His real name is never mentioned in the series, nor is much of his past revealed. Heero often appears cold and emotionless, but is in reality quite a caring individual who simply prefers to keep his emotions private. Pilot of Wing Gundam. Piloted Gundam Epyon temporarily before switching machines with Zechs Merquise. Pilots Wing Zero Gundam for the rest of the series.

Duo Maxwell
Duo (often abbreviated as "2") grew up as a homeless child on the streets of L2 (one of the five colonies, the others being L1 and L3-L5), and became second in command to his gang leader, Solo (who gave Duo his first name). When Solo died, Duo was adopted by the Maxwell Church, from which he took his last name. Upon the ransacking and subsequent burning of the church, Duo ran away and was recruited to fight for the colonies. He is cheerful despite his traumatic past, and one of the only outward signs of his past is his decision to call himself the God of Death, in reference to a conversation he once had with a sister of the Maxwell Church. Pilot of Gundam Deathscythe/Deathscythe Hell.

Trowa Barton
Trowa (often abbreviated as "3") grew up as the mercenary soldier No-Name. When the mercenary company which raised him was killed--mostly by Trowa, who believed them to be spies--he set off to find a home and place to stay. He joined the Barton Foundation, a group which makes weapons, and eventually, when the actual Trowa Barton was killed, No-Name took his name. Due to his past history, Trowa is stoic and unwilling to show any kind of emotion. However, he truly does care about others, and has been known to put himself in danger to save others. Pilot of Gundam Heavyarms.

Quatre Raberba Winner
Quatre (often abbreviated as "4") grew up wealthy as the youngest (and only) son in a family of thirty children. He is also the only natural-born child, though he does not know this fact. His family owns the Winner Corporation, a mining company, and they are firmly dedicated to non-violence. When Quatre ran away from home at sixteen, he met the Maganac Corps, a group of Middle-Eastern fighters. Quatre earned their respect, and later came to lead the group. He later chose to pilot a mobile suit to protect the colonies, going against his family's non-violent principles. Quatre is warm-hearted and open, often appearing to be the most childish of the group. Because of his privileged upbringing, he can sometimes come across as ignorant of certain things, but he truly cares about his family and his comrades. Pilot of Gundam Sandrock.

Wufei Chang
Wufei (often abbreviated as "5") grew up in a relatively well-off family, allowing him to devote himself to learning and thinking. At sixteen, he was married to Meilan through an arranged marriage, and initially disliked her and disdained her propensity towards violence. However, when she took it upon herself to protect the colony and died in the attempt, he came to admire her courage and vowed to carry out justice in her name. Wufei is reserved and looks down on those he deems weak in body or spirit. Initially, this causes him to disdain working with others, though he later comes to accept that he must in order to bring about the justice he so craves. Pilot of Gundam Shenlong/Altron.

In Fanfiction
The Gundam fandom is moderately popular, especially among slash fans. Because all of the main characters are young, relatively attractive men, fanwriters often pick their two (or three) favorites and thrust them together. The most popular parings are Heero/Duo (often abbreviated "1/2") and Trowa/Quatre (3/4), with Wufei thrown in as the token straight man of the group. This can be done well, just as any pairing can be done well, but it is a sad reality that much of it is not.

A widely read slash goodfic has been written by Sunhawk16, and is hosted on Sunhawk's GW Fanfiction. The Ion Arc features the usual slash pairings (1/2 and 3/4), and is complete. (Quick warning: the finished work is over one million words long; reading in a single sitting is not recommended. Also, some parts may be NSFW, due to details of a mildly graphic nature.)