Nepgear and Neptune have a close sisterly bond. Neptune has put effort to making herself a "cool older sister" for Nepgear. Nepgear has also never been disappointed by Neptune despite Neptune's lack of care for her work as CPU. When Neptune tried to do an excessive amount of work to show that was cool, Nepgear reminded her she likes to regular carefree Neptune. Nepgear looks up to Neptune and they play a lot together. Nepgear hates it when anything harmful happens to her sister. In the end of Mk2 and Re;Birth2, Nepgear becomes a bit more assertive pushing Neptune to do her work for once. Neptune preferred the pushover Nepgear but realizes that Nepgear has grown up.