Madara uchiha with her self-proclaimed servant Kira Uchiha were on their way to get the sealing scroll from obito after they had finally casted the infinite tsukiyomi on the whole world.. damn, they evil. Both lord/master and the self-proclaimed female slave had been childhood best friends. As they grew up, Madara went evil for his non-evil plan and kira never left his side; cuz she loved only a few things: science, peace and.... madara.

Another reason was that she was a close relative of his. Madara had always been stoic, making kira yearn for his attention but never giving her any. As they keep walking, kira keeps on rambling some nonsensical shit (she is an introvert and rarely talks btw) and Madara ignored her. Then he finally says after sighing:

"Shut up for once, you hindrance."