Lumen

ルーメン
Another member of Midoris unit. Possesses a mans voice but a womans body and speech pattern. He/She fights with a long metallic whip and can summon a fishlike Slave called Ketos. It is revealed that Lumen was killed during the assault on Cardair due to his/her body expiring. It is also hinted that Rad will also suffer this fate soon. In Yohkos picture it clearly depicts a young woman. It is unknown whether or not this is Lumen but it most likely is due to the height. Source: Wikipedia