Unlike Hatsune Miku and Kagamine Rin and Len, Megurine Luka's costume is not based on a school uniform. This is probably because Luka has a "moody yet husky female voice" with a "cool, somewhat mysterious" character. One of the first few songs produced, "RIP=RELEASE" took the number one spot on the 70th Weekly Vocaloid Ranking. The song earned 843,233 points during its first week, the highest one-week score ever recorded.
Beautiful MoeHaku Luka! I didn't even know this was her official costume until I received this contribution. Thanks, Wikia!