Android 21 was created at the same time as her siblings, Androids 17 and 18, even though her number is higher than 18.
21 has long, brown hair and light blue eyes. She greatly resembles her sister, 18.
Much like her sister, 21 often gets fed up with her brother about destroying everything. She is ruthless and merciless. Upon joining the Z Fighters, however, she becomes much more caring and kind.