Like Yami, Mea is a transformation weapon that was created by Tearju. Though not also created from Tearju's DNA, she is still considered to be their younger sister. Mea came to Earth by orders of her master Nemesis to bring Yami back into space as her cold-hearted assassin old self and wants her to be the ultimate weapon that is unstoppable by anything and anyone, but Yami encouraged her to try and embrace humanity, which she slowly does with the help of Rito, Tearju, Momo and Nana. Yami shows a slight care and understanding towards Mea. She deeply cares for Yami which is shown when she was desperately trying to return Yami from the way she was before becoming "Darkness."