Yuuka is the twin sister of Sawana Arisato. After Sawana left her home and joined the Cult, Yuuka began to search her. Yuuka is a part of Sawana, the Arisato-Clan transform their child into tiwns, one of them is bad, the other one is nice. Yuuka is nice part of Sawana, but Sawana was the girl that was born, so Yuuka is a Transformed Person.