Right now there's a war between the vanities
But all I see is you & me, the fight for you is all I've ever knownZechs Merquise/Millardo Peacecraft. Zechs Merquise is a man of many names -- Zechs Merquise, Millardo Peacecraft, the Lightning Count, and Preventer Wind all refer to the same person. He is a man of duplicity; he wears a mask under the impression of concealing a facial deformity but in fact uses it to hide his true identity: the man that calls himself Zechs Merquise, Lieutenant Colonel of the OZ Faction, is in actuality Millardo Peacecraft, the heir to the pacifist Sanc kingdom destroyed by the United Earth Sphere Alliance. He seeks to avenge his homeland by joining the organization that destroyed it by infiltrating it slowly from the inside. However, his growing disgust with the state of warfare on the planet Earth leads him to accept the position of leader of the rebel organization White Fang. Zechs seeks to end warfare by becoming war -- in other words, he becomes a symbol of destruction. By firing a Libra canon at Earth, he hopes to unite citizens and help them realize the futility of warfare. At the end of the series, he sacrifices himself by self-destructing the mobile suit he was piloting in order to save the world. Although presumed dead, he reappears one year later in the sequel Endless Waltz.
Lucrezia Noin. Descended from Italian nobility, Lucrezia Noin is a steadfast woman who is introduced as an OZ instructor at the Lake Victoria Academy. Instilled with a strong sense of loyalty and motherly protection, Noin is a woman who knows her ideals and sticks with them. She is a woman who is intensely loyal to Zechs and would probably do anything he asked her to -- in fact, she left OZ to act as a royal guard to Zech's sister, Relena Peacecraft upon his request. She is one of two people who know his true identity as Millardo Peacecraft, as she is one of the very few people who ever get to see him without his mask on. Upon Zechs' presumed death, Noin was the only person who believed he was still alive.
The Relationship. While a true romantic relationship between the two is never really confirmed, there are hints scattered in Gundam Wing that could indicate otherwise. At the very least, Zechs and Noin are two people who know each other and trust each other deeply -- the relationship between Zechs and Noin remind me much of that between Roy Mustang and Riza Hawkeye in Full Metal Alchemist (undying loyalty, unspoken subtleties, silent understanding).
Their background with each other is mostly shaded in mystery. Zechs and Noin first met each other at the Lake Victoria Academy as cadets and were at the top of their class; Zechs ranked first, while Noin ranked second (however, Zechs makes the off-handed comment that Noin "let him"). Their relationship may look extremely one-sided at first -- Noin has a sort of personal Zechs picture shrine/gallery/what have you that may seem kind of creepy, and she openly admits to Zechs' sister Relena that she loves him. She attempts to defend his actions when he seeks to destroy the world even though she doesn't completely understand his actions. She gives up her position at OZ to become Relena's bodyguard at the request of Zechs. She supports him when he's injured, when he's not injured, and when he needs it. Anything Zechs wants, she does.
However, I don't feel that their relationship is as one-sided as it seems. He takes extreme care when helping her out of a damaged Leo suit; Noin is one of very few individuals who he lets see him without a mask on (thus showing her his "true" nature); Noin is one of two people who know his true identity in the beginning of the series; she is one of the very, very few people who he trusts wholeheartedly -- so much so that he asks her to look after his beloved sister. When Noin doesn't understand his actions, she tries to stop him -- even at the cost of her life. She comes within inches of his mobile suit many times, and despite Zechs' frequent warnings and orders to get out of his way, he never kills her. While Zechs never addresses his feelings for her opening, I believe that Zechs has some sort of strong feelings for her, whether it be a deep sense of trust, love, or appreciation.
6x9. "6x9" is commonly used to refer to a romantic relationship between Zechs Merquise and Lucrezia Noin -- "zechs" is German for six, while "noin" is German for nine.