Who would've thought that Tadashi Yamaguchi Has an older sister? (Y/N) Yamaguchi is a 3rd year in Karasuno. She's just like her brother, shy at the start but once you get to know her she opens up. (Y/N) had nothing to do with the karasuno boys volleyball team until her brother came to karasuno. Ever since then her quiet life changed. I do not own haikyuu or any of the characters Also warning for curse words!