Ghost

Ghost is a character that NovelAI introduced during "Twitch Chat and I invaded Space with Artificial Intelligence". Ghost was originally an assassin sent by the humans of Earth to defeat the emperor of the Chatern Empire, but Ghost fails and instead became the Chatern Emperor/Empress.

The AI writes Ghost with inconsistent gender, sometimes referring to Ghost as a "he" or a "she", and as an "Emperor" or "Empress", so Ghost is probably gender fluid or something.

Even though Ghost is the emperor (and apparently empresses as well), Ghost is also somehow the emperor's wife, and Ghost also impregnated the Empress, who gave birth to twins, Arbiter Junior (who is normal) and Arbiter Senior (who is a clone).

Origins
Ghost was originally an assassin sent by the humans of Earth to kill the Chaturn Emperor, because they were pissed that the Chaturn Empire's Death Star exploding during construction and killing everyone on Mercury. But Ghost failed to kill the Chaturn Emperor, and instead took his place.

As the Empress of the Chaturn Empire
Ghost is a master of martial arts, and he used these skills to become a powerful empress. He quickly conquered the Empire of Chaturn, but during his reign he suffered from sever delusions of grandeur and invented the evil anti-matter bomb.

The humans of Earth were pissed, and decided to build a giant robot called Arbiter, a genetically-enhanced human soldier who has been trained to fight aliens, and they send the Arbiter to defeat the new Chaturn Emperor.

Arbiter defeats the new Chaturn Emperor, but then he comes face to face with Ghost, who had became the Emperor's new wife (Ghost is their own wife?). Arbiter falls into a deep depression and thought that all of his efforts had been in vain.

After Ghost impregnated the Empress (herself ), she gave birth to twins. One twin was normal and one twin was a clone. The normal twin is named Arbiter Junior and the clone is named Arbiter Senior. The Arbiter Twins would be send by the humans of Earth to destroy the new Chaturn Empire, and they defeated its new Death Star.