Millis Steel is a famous Pokémon bandit that was attempting to catch
Diancie in order for it to make diamonds for her. Her father is
Argus Steel. She worries about her fathers health as he eats too many chocolate.
She pretended to be looking out for
Diancie when she rescued her from Team Rocket but she had been spying on
Diancie to know when the right time was to attempt to capture it.
In the movie credits, she and her father are seen running a chocolate shop.