Luka Megurine is a VIRTUAL SINGER who watches over the various SEKAIs: School, Stage, Street, Wonderland, and Empty. In all SEKAIs (except Empty), Luka takes on the personality of a cool, mature, and loving young woman that often serves as a mentor figure. In the Street SEKAI, Luka is a carefree girl who does whatever she pleases, and in the Wonderland SEKAI Luka is constantly sleepy. In the Empty SEKAI, Luka is cold, closed-off, and blunt, but protective. 

Voice: Luka has a cool, delicate, and mature voice, that differs slightly depending on which SEKAI she is in.

Reference: https://youtu.be/lHsLKUW0VZI

Note: By voicing Luka, your vocals will be slightly altered to sound more robotic. You will also be taking on the responsibility of voicing several female NPCs, as the VIRTUAL SINGERs (besides Miku) are the least prominent characters. If vocal alteration makes you uncomfortable, or you'd rather not voice multiple characters, do not audition for her.