Keiram is demon blade with the power of dark magic. Since the power of the demon blade come from the (God of Black Fog) Aer.So Aer consider her as the daughter. In chapter 19 when Cyan Vert meets with Aer for the first time in this current timeline Aer give some of his life force to Keiram. which helps Keiram to materialize her body without consuming any mana from Cyan Vert.