Neptune is one of the four goddesses of Gamindustri. Her main color is purple and her nation is Planeptune. She tends to be pretty lax when it comes to running her country; in fact, she's probably too lax for her own good. This bubbly, happy-go-lucky girl would rather play video games with her friends than do boring things like working. Though when she does put her mind to a task, she's sure to see it through to its end.

With others, Neptune is somehow able to get along with anyone. She doesn't have any negative relations with anyone, aside from evil villains of course. She's even close with the other goddesses of Gamindustri, even though they're supposed to be competing for resources. But nothing beats her relationship with her younger sister, Nepgear. They're as close as sisters can be, even when Nepgear has to pick up the slack for Neptune's laziness.

As a goddess, Neptune can perform HDD transformation. In her HDD form, she is not only stronger but bigger too. Her personality has also been known to radically shift from her carefree self to a more controlled, mature one. Some people would prefer her with this personality, but her sister loves her just the way she is.