Angol Moa is the "King of Terror", who is ditzy and insecure as a result of her impact from space. She was sent to planet Earth to arrive in July 1999 for Earth's destruction, as predicted by Nostradamus, under orders from her father. She states during her first appearance that she told Nostradamus to deliver a message to the humans warning them of her arrival. In the anime, she arrives 500 years too early and takes a nap in orbit, until she wakes up in 2004, 5 years too late. In the manga, she lands near Fuyuki, while in the anime, she lands on Giroro's tent. In both, she is taken into the Hinatas' home, where she is nursed back to health by Natsumi. When she wakes up, she reveals her true form and starts to destroy the Earth, until Keroro, who arrives later, is persuaded by Fuyuki to stop Mois. The Angols use seemingly magical weapons to destroy planets. Her weapon is the "Lucifer Spear", which, when not in use, looks and functions like a cellphone. When she is using her attack, "Hellmageddon", the Lucifer Spear becomes a golden staff with a crescent moon on one end and a meteor on the other end. She uses the meteor end to initiate Hellmageddon. She is close friends with Keroro, who she calls oji-sama, which means, roughly, "uncle". Whenever she sees anyone hitting Keroro is any way, she transforms and uses a watered down version of Hellmageddon, which usually catches others, including Keroro, in the blast. Tamama often competes with her for Keroro's attention (and affection). Her transformation sequences, stylized costume, and related accessories may make her a parody of the magical girl genre. As an added note, Mois' Pekopon form wears a hair clip explicitly in the shape of the Science Patrol's Ryuusei-mark in the anime (while the girl whose form/soul she "borrowed" has a Ultra Garrison-mark hair clip). Her name is frequently used in puns on the Japanese phrase moe-moe, which usually refers to a cute girl who appeals to older members of the audience.

To blend in with the Earth people, Mois also transforms into a tanned, bleached-blonde teenage kogal who is always seen in a school uniform and loose socks. Her true form is a pale gray-haired girl who wears a purple-and-white magical girl costume. Although the King of Terror, she is anything but terrifying. She's sweet, clumsy, and peppy but can be scary when she's in Angol form, and uses her Lucifer Spear to split the Earth. She got her Earth-look from when she first arrived in 1999 (2004 in the anime), before she met the Hinatas. In the anime she saw a teenage girl (named Masami) who was beating up some thugs in order to protect her friends. Amazed by her courage, she decided to be like that girl and chose her appearance as her Earth-form. In the manga she saw a girl shake off her friend/underling and decided to become like her, following her father's advice to think only of herself while on her mission.

Source - Wikipedia