Darkness

Darkness is the innate and prohibited transformation of Yami, and it is the uncontrolled and unlimited form of transformation. If the means of release is wrong, it would become the dangerous power that even overwhelms Nemesis. If Yami sincerely accepts the traquility of mind, it activates. Therefore it is set as a trap against the universe that ceased the Galactic War and is goint to peace. Darkness is reinforced when Yami feels an excessive stress to her mind however after it became bugged because of Yami love for Rito and with help from everyone spreading the bug further to return Yami to normal she gained the abililty to use it at will.