She was created in a government lab and her heart and brain are a computer, probably an Apple.    Though she claims to be invincible, that is up for question.

Neko, also referred to as the Evil Neko Chan, was determined to rule the Earth.   She intended to do this with an army of felines that are subservient to her will.

It turned out the reason she wanted to rule Earth was because the banana-martians were prohibiting her from ruling other planets.    When the banana-martians were turned into banana daiquiris by the cognitive transmogrification gun this opened up new possibilities for her.

When offered the option of drinking the banana-martians turned banana daiquiris she agreed to spare the Earth.

Earthings, at least the ones who knew about her evil plot, were grateful.

Though no longer a threat to the planet, it is unwise to cross her on an individual basis.    She is still prone to assassinate people who forget to take out their garbage, get their mail, or litter.

She also fights crime in the sewers.

When she can not find any of her enemies she picks fights with random hobos and then flies away to the moon.

There are no current reports on how the people on the moon feel about this.