Emberiza is originally a human whose father and mother were attacked by a hollow before she was born, resulting in her acquiring fullbringer powers. Being a child prodigy with high intellect, Emberiza was able to master her powers at a young age. Following the event of Aleherlot's massacre, a young Emberiza is kidnapped and had her body modified into a bio-weapon, explosively enhancing her physical abilities but erasing her memories in the process.