Melissa Mao is a private military contractor from Mithril. She's Chinese American and a former Marine.
Melissa is very proficient in use of an Arm Slave, however she lacks exact control. She tends to use fast and furious methods in her firearm use. Later in the series she usually does not pilot an Arm Slave, but she can still pilot excellently, although her capabilities are nowhere near those of Sousuke Sagara and Kurz Weber. Aside from English, she can also speak fluent Cantonese due to her time spent in Hong Kong, particularly in Kowloon.
Melissa is a ruthless insulter and an extremely heavy drinker, She is shown once having many cigarettes and a minimum of 20 beer cans sprawled out on Tessa's coffee table. She is extremely rude, preferring to use heavy language when talking to someone angering her or someone she can not stand. During Sousuke is training rugby players, he is shown using extremely heavy language based on the training manual Melissa gave him—language inspired and quoted from R. Lee Ermey's lines in Full Metal Jacket; appropriate, since Mao was a Marine Corps drill instructor. She also enjoys a practical joke or two. Once in the series when Sagara called to protest Tessa's staying in his apartment, she gave him permission to "jump her bones", obviously aware of Tessa's feeling for him. But in the next episode when Tessa again found herself in his bedroom, Mao was there and she handcuffed Tessa to herself to keep her from sneaking into his room.
Born to Chinese-American parents on May 11 in New York City, New York in 1976, she was brought up under strict Chinese traditions that included her supposed arranged marriage. When she realized it, she left home and immediately joined up with the United States Marine Corps, entering the recruitment office while still in her wedding gown. After several years of service, she was eventually given a dishonorable discharge. Up to now, Melissa has bitter feeling with her father, who had been in the United States Air Force. After leaving the Marines, Melissa went to Hong Kong, then under British control, and stayed with some of her maternal relatives.
Scouted by MITHRIL, she was given the codename Urzu-2 by Gail McAllen and was given the command of her own team until two of her comrades were permanently injured while on active duty. Because of this, she was forced to head to MITHRIL's secret training camp in the forests of Berutarube in order to select her new replacements. Melissa was initially intrigued by Kurz Weber despite his poor marksmanship, but he was promptly taken off the list of potential candidates after Melissa experienced firsthand Kurz's womanizing attempts. Sousuke Sagara was not even considered one of Melissa's potential candidates, due to his low test scores and seemingly overall mediocrity. It was only by chance that Melissa noticed him during an AS simulation test. It was there that Sousuke skillfully piloted an Rk-92 Savage and defeated an M6 operated by a top-scoring recruit.
After the Berugan president had called MITHRIL personnel in Berutarube to rescue his kidnapped daughter, Maria, and eliminate a communist rebel cell, she was left with Sousuke, Kurz, and Jimmer after a first strike attempt had netted the capture of most of the MITHRIL instructors and recruits.Realizing that Sousuke and Kurz were hiding their skills from her, she forced them to come clean and ordered them to battle with the guerrillas, overpowering their ASs and forcing the rebels to surrender. She eventually decided to let Sousuke and Kurz enter her squad as the new members. Afterwards, she was sent into Tokyo with the rest of her squad to guard Kaname Chidori. Nearing the end of the first series, she was wounded by Gauron during AS combat at a U.S. chemical weapons disarmament facility on Berildaobu Island, Republic of Perio. Although she was mostly incapacitated, she managed to assist Kurz in killing Guen Bien Bo by tossing surgical scalpels into him, a skill that she did not show until near the end of the anime.
Melissa is a friend to Tessa and as such, has access to her office.
Early on in her MITHRIL career, Mao was good friends with Gail McAllen and Belfangan Grouseax, both soldiers who later became commanding officers of Tuatha De Danaan's SRT unit. This friendship has helped her maintain a good working relationship with both men, although Grouseax asked her to hide his friendship with him and McAllen from the SRT troops.
With the heavy losses suffered by the Special Response Team in the defense of Merida Island, Mao has become the second in command of the SRT.