Yuu Matsuura

Yuu Matsuura (松浦 遊 Matsuura Yū) is the son of Chiyako Koishikawa and Youji Matsuura.

Physical appearance
Throughout the series, Yuu Matsuura is known to be a very good looking young man. He has blonde wavy hair that reaches his neck and his clear brown eyes highlight his light face. He is often seen wearing his school uniform, however on his own time he tends to keep things simple with a pair of jeans and comfortable hoodless sweatshirts.

Personality and traits
Yuu Matsuura is often likened in personality to that of Meiko Akizuki, Miki's best friend. Like Akizuki, Matsuura is calm and collected and somewhat mysterious, even to the people closest to him as he tends to bottle all of his emotions up so as not to be a burden on anybody else. He is generally kind and "cool" as described by Miki when she first met him. He is said to have a poker face. He is quick witted and loves to tease people in an amiable manner.

Miki Koishikawa
The relationship between Yuu and Miki starts out bumpy due to their contrasting personalities but soon turns into a love that touches the hearts of even the other characters.Yuu admits to admiring Miki's ability to show her emotions clearly, and it being one of the reasons he fell in love with her. Yuu teases Miki a lot, but this is his way of showing affection for her. They're both loyal and honest to each other and stay in love even after many hardships that both of them face together. Their first kiss is a complete surprise for Miki because she had only met him a few days prior at an introductory dinner attended by both their families. At the end of the anime, they marry; in the manga, they are making plans to marry after college. In Marmalade Boy Little, after living together for 13 years, Yuu proposes to Miki and they get married. They later have two children together named Fū and Kokona.

Arimi Suzuki
She is a former classmate of Yuu's at his previous high school. She convinces Yuu to be her "boyfriend" for three months, during which they act as a couple on a trial basis. Arimi attempts to make Yuu to fall in love with her during this time, but fails. At the end of the three months, he still thought of her as a friend. Miki's indecisiveness about Ginta and Yuu frustrates her, as she does not think that Yuu deserves someone who cannot commit to one person. Arimi teams up with Ginta in an attempt to drive Yuu and Miki apart from each other. However, she eventually realizes that Yuu's behavior around Miki indicates that he does like her, so she stops her pursuit of him. Some time later, she develops feelings for Ginta and they become a couple.

Suzu Sakuma
Suzu first fell in love with Yuu when she first saw a picture of him at Chiyako's office. She is immediately smitten with Yuu. Suzu wanted Yuu to appear in the commercial that they're shooting with her. She also begged Satoshi to get him as her math tutor.

In the manga, she doesn't want Yuu to herself, she wants Yuu and Meiko to get together because she believes that Meiko is perfect for him. In the anime, Suzu wanted Yuu to be her boyfriend and kissed him when he was performing on the stage.

Youji Matsuura
Youji is Yuu's biological father. Yuu believed that Youji wasn't his real father because of the letter he had found that was written by his grandmother.

Chiyako Matsuura
Yuu's mother, who is a very good cook. She works for a cosmetics company. Yuu's relationship with his mother is quite strained due to the affair she had Jin, Miki's father some time ago.

Jin Koikshikawa
Jin is Yuu's step father. It is shown that that the two have a father-son relationship like in episode 2 when Yuu teased Jin because he's bad at playing video games. Yuu thought that Jin is his biological father because he found his parents' college yearbook where he saw that his mom was with Jin. It is revealed that Jin wasn't his father after all because his mother had a miscarriage and then had him with Youji.

Rumi Koishikawa
Miki's mother, infamous for her bad cooking. She is cheerful and sweet, and like her ex-husband, a little childlike as well. She works at a cosmetics company. She was married to her old friend Jin Koishikawa, later divorced him on good terms, and married Youji Matsuura, her old flame. Yuu and rumi have a nice relation. for her birthday yuu bought her a pair of earings which she loved

Rikka Matsuura
Rikka is Yuu’s younger half-sister; they share the same father. According to Rikka, Yuu was her first love when she was little. Yuu is a doting older brother to Rikka.

Saku Koishikawa
Saku is Yuu’s younger half-brother; they share the same mother. Saku looks up to Yuu.