Code Geass: Nightmare of Nunnally

A re-imagined, alternate reality Code Geass manga Nunnally, the sister of Lelouch, encounters the being called "Nemo" that heals her body and grants her the power to summon the Knightmare Frame Mark Nemo. Using her new-found powers, Nunnally seeks to find her missing brother, but her actions arouse the interest of the elite Britannian forces.