Lumen is a pop star promoted by the media-owning
Sumeragi Group, and is currently the most popular idol in the
nation. However, Lumen is but an avatar; a projection created
by Joule’s septimal power, which takes on an entire form of its
own completely separate from Joule. Unlike Joule, she has a
very strong personality and is very much a free spirit.
According to Lumen, however, this is just a manifestation of the
person Joule truly wants to be. Even though the Sumeragi Group
is promoting her as a pop star, she is in fact being used to locate
other adepts that resonate with her ever-powerful Muse ability.
These adepts are then found and captured by Sumeragi.