Midoriko is the first LRIG of Hitoe.

Soon after Hitoe loses her second WIXOSS battle, Midoriko tells her to abandon her so she wouldn't have to become an Eternal Girl after she takes over her body to leave Hitoe to transform into a LRIG.
In the last episode of the second season, Midoriko is seen on a bus in her human form meeting Hitoe again.
In Selector Destructed WIXOSS we discover that her real name is Ichikawa Midori.