Achlys

Achlys (不変靄, Achlysu) better known as Mist of Death (死の霧, Shi no Kiri) is the Phoenix of "Eternal Night" and "Darkness" and has often been mistaken to be the personification of death and despair. Achlys appears to be the only female phoenix besides the Phoenix Queen and is the only phoenix that has directly never shown to be capable of using Avatar Magic. While it maybe possible that Achlys is capable of such feat but she prefers on using her ability to shapeshift in general to take whatever form she pleases.