Yuy, Heero

Heero Yuy is nothing more than his code name, however, named for the fallen Colony leader who's assassination the Gundam Pilots were supposed to avenge.

After his arrival on Earth, Heero encounters Relena Darlian, the daughter of an Earth/Colony peace advocate. After enrolling in her school, Heero ends up saving her life on several occasions, causing him to confuse his mission and his feelings.

Heero's first ally is Duo Maxwell, who helps him pull his Gundam up from the ocean. Afterwards, he sets out on his own for a while, attacking bases and OZ encampments.

His primary rival is Zechs Merquise, and they have several battles throughout the series, even trading Gundams from time to time. His other rival is Treize Kushrenada, who gives him the purely evil Gundam Epyon, which he trades to Zechs for the Wing Zero.

Although Trowa Barton holds the most mystery to his personality, Heero comes a close second, always disappearing after completing a mission or having an encounter. He lives by his emotions as stated by himself several times within the series and always thinks things through most of the time. He was also referred to as "the heart of space" by Quatre Raberba Winner, Pilot 04, near the end of the last episode.

In Frozen Teardrop

[Spoiler] At an unspecified date, Heero is cryogenically frozen by Preventer and stored at the Mars Preventer base. Given the code name 'Sleeping Beauty/Princess Aurora' due to the appearance of his capsule, he remains there for decades until he is awoken in MC (Mars Colony) 0022, when he is awoken to participate in Operation Mythos.

After awakening, Heero is approached by Master Chang and Father Maxwell, who ask him to fight again in one last mission. For this purpose he becomes partners with Duo Maxwell and becomes the pilot of the "Snow White," vowing to kill Relena once again. [/Spoiler]