Len is a surly, quiet and rather cold violinist who normally behaves contemptuously toward and around everyone. He is a child prodigy, coming from a family of renowned musicians. His mother, Misa Hamai, is a very famous pianist and his father is a well-known violinist. Because of this, many people take his brilliance for granted. He seems very cold towards those that he comes into contact with, even his admirers, to whom he rarely pays any attention.

Before he met Kahoko he didn't believe music was enjoyable, though after spending time with her, Len slowly began to enjoy music and his music changes because of her. He slowly warms up to Hino and even gives her advice on how to hold and stand properly with the violin. People think that he acts harshly towards Hino, but deep down in his heart he is really concerned about her (though he may not show it). As the series progresses, he realizes his feelings for her. He never openly confesses to have such feelings for Kahoko, but he sometimes show his concern for her by helping her get her violin fixed when the strings snapped, and giving advice on violin playing. He's slowly affected by Hino and his mother says that he has changed his character. He can play the piano as well, which may be due to the influence of his mother (who is a renowned pianist). It was said in chapter 52 of the manga that Len will go abroad to study.

(source: Wikipedia)