PlotKeiichi Morisato is a good-natured, yet hapless and girlfriend-less college freshman who is often imposed upon by his elder dorm-mates and brow-beaten into taking phone messages and doing miscellaneous chores for them. One day, while alone in his dorm, he accidentally calls the Goddess Technical Help Line and a beautiful goddess named
Belldandy materializes in his room. She tells him that her agency has received a system request from him, so she has been sent to grant him a single wish. Skeptical and thinking someone is playing a practical joke on him, he wishes that she stay with him forever. To his surprise, his wish is granted. Belldandy must stay with him, but as his dormitory is strictly male-only, they are both forced onto the street.
They set off on his motorcycle to find alternative shelter, eventually seeking cover in an old Buddhist temple. In the morning, they are greeted by the temple's sole inhabitant, a young monk, who welcomes them and gives them permission to stay until they can find permanent lodging. He immediately puts them to work maintaining the temple grounds, but when he sees Belldandy use her powers to save Keiichi from injury, he begins to fear that she may be a demon or sorceress. He is eventually convinced of Belldandy's intrinsic goodness when he witnesses her solicitous care of the temple premises and her perfect meditation ritual. When he decides to go on a pilgrimage to India, the priest gives the couple permission to remain in the temple so long as they continue to maintain it.
Characters

Keiichi Morisato (森里 螢一 Morisato Keiichi?) is a student of the Nekomi Institute of Technology and a member of the NIT Motor Club. One day Keiichi accidentally dials the Goddess Relief Office. After summoning Belldandy by accident, he ends up wishing for her to be by his side forever. Ever since, the two have been together. Keiichi's pure and innocent personality also puts him in the middle of an unusual love relationship. While he understands his love for Belldandy, he sometimes has a difficult time expressing his feelings.
He is a very skilled mechanic and an exceptional race driver. He is bestowed the directorship of the Motor Club, which he subsequently passes on to Sora Hasegawa. At his supposed graduation from college, he started working at the repair shop Whirlwind owned by the founder of the NIT Motor Club: Chihiro Fujimi. He picked up the one class and actually graduated many chapters later.
Since he met Belldandy, Keiichi has had many extraordinary experiences in his young life, including having met several other Goddesses and supernatural beings. He became the only person ever to have flown the Shinden, an experimental World War II Japanese airplane, and met Schrodinger's Whales - and saved them from extinction by teaching them songs.
Keiichi's personality is illustrated when he summons one of Lind's own Angels, Cool Mint. Lind gave him one of her angels because he is able to host the angel with the love of the three goddesses, which he received due to his innocent personality. Later on, Keiichi also temporarily and involuntarily hosts the demon-angel Blue Lance. The reason why the angel chooses him to be the host at random was explained as that he is the only person referring to her as an "angel" and not a "former demon".
Belldandy (ベルダンディー - Berudandī?) is a goddess that ends up contractually bound to Keiichi Morisato after he accidentally dials the Goddess Relief Office. Ever since, Belldandy dwells with Keiichi at the Tariki Hongan Temple in the city of Nekomi, Chiba Prefecture near Tokyo. She can cancel the contract at anytime, but she states Keiichi is a special person in her heart, and that her purpose is to make him happy.
Belldandy is kind, patient, and warm, not only to Keiichi, but to everyone, without exception. She can easily sense other people's emotions, and tries her best to be empathetic to all those around her. However, even though Belldandy tries her best to be as kind as possible, it is revealed that at times, as a result of latent jealousy, she can become very insecure and sad, especially when she is confronted with an implication that involves Keiichi in one way or another. This can sometimes result in power leaks that affect everything within the vicinity, referred to as "jealousy storm" in the anime.
Belldandy is licensed as a goddess first-class, unlimited, and as such is highly skilled. Her power is so great, in fact, that she is required to wear a special earring on her left ear which constantly seals the full brunt of her magical strength. Belldandy's angel is Holy Bell; her elemental attribute is wind. Like all angels, Holy Bell augments Belldandy's magical powers when called upon, and like all angels, she also reflects her master's current state.
Urd (ウルド Urudo?) is Belldandy's older half sister and is the second Goddess to appear to Keiichi. Urd ranks as Goddess second class, management category limited license, similar to her youngest sister Skuld. She is the Yggdrasil System Administrator and Manager. Though she is much more powerful than her sisters, she has not become a first class goddess, most recently because she chose not to become a first class goddess (See main article.) Urd shares a common father with her younger sisters, but has a different mother, the Demon Lord Hild. Because of this, Urd is a hybrid of Goddess and Demon, reflected in the half-white, half-black appearance of her Angel, World of Elegance.
Urd fancies herself a Goddess of Love, so she comes to Earth to spur Keiichi onward with love potions and well-meaning, but deceitful advice, but as punishment for deserting her post and for using her powers on Earth without authorization, The Almighty banishes her from Heaven until further notice. After being allowed to go back, she decides to stay on Earth instead.
Skuld (スクルド Sukurudo?) is the younger sister of Belldandy, and is the third Goddess to appear to Keiichi Morisato. Skuld has a Goddess second class, type one, limited license, a category similar to her eldest sister, Urd. Skuld is one of Yggdrasil's system debuggers. She compensates for her lack of magic power with her innate talent for invention, which is known throughout Heaven. Skuld is an engineering genius, capable of building just about anything out of the most mundane parts under most limited resources. She can compute equations and redesign even the most complex engineering blueprints in no time.
She travels to Earth after Belldandy's proximity to Keiichi started creating an increasing number of bugs in Heaven's supercomputer Yggdrasil. At least that was her official excuse, as she believed Belldandy was living with Keiichi against her will. She tried to convince Belldandy to return to Heaven to resolve the bug problem and at the same time with the ulterior motive of alleviating her loneliness. After realizing that Belldandy's relationship with Keiichi was not going to end any time soon, Skuld decides to stay on Earth and act as Belldandy's unofficial chaperon.
In the second season she begins to develop her goddess powers. Her angel's name is Noble Scarlet.
Heaven
Heaven is one of the two divine factions in the series. It is where the three main goddesses and several other characters reside. It contains,
Yggdrasil (ユグドラシル Yugudorashiru?), the heavenly computer system that maintains reality, with the Gods and Goddesses acting as its programmers, system administrators, and debuggers. Yggdrasil works with the Goddess Relief Office by notifing the goddesses such as Belldandy working at the office of people whose fortune and misfortune is out of balance given their actions such as fortitude in facing misfortune, kindness in sympathizing with others. Each person Yggdrasil chooses is granted one wish which can be anything ranging from "wealth that would last a life time" to the destruction of the world, or even for simply a "Girl like you".
Almighty
The Almighty One (神様 Kami-sama?) is the lord of Heaven. As Lord of Heaven, all Goddesses ultimately answer to Him and He is responsible for maintaining reality, time, and probability as we know it. His attitude and personality is very commanding, but He is very polite and forgiving; he has forgiven the Norns for disobeying his orders multiple times (as is suggested by Keiichi in the manga). The Almighty One is very blunt and straight-forward. He doesn't understand how humans act and communicate; possibly because He hasn't been to Earth in a long time. Throughout the manga and anime He is an unseen character as viewers never see His face, which is usually shrouded in shadow, turned away, or simply too close-up; all that can be discerned is that the Almighty One is tall and well-built, with long black hair. He also has many seals on His hands, neck and on His ears (this could probably be a clue as concerns the fact he may be the divinity in doublet with Hild, as also we can imagine listening to her discussing on the Double System). Many people affirm The Almighty be the father of the three Norns, but He has never been identified as such in either the manga or the anime.
HellHild (ヒルド Hirudo?) is the ultimate Demon who is the opposite to The Almighty, known as the Ruler of Demonkind. She is incredibly powerful, with her power dwarfing even the combined strength of the three goddesses. Despite her immense power, she respects the doublet system, and thus limits her power to prevent killing any of the Goddesses. She is Urd's mother, whom she loves deeply, though Urd doesn't return the feeling (it is revealed that doing so would mean that Urd would acknowledge and thus be taken over by her demonic side). Hild dislikes Belldandy, because Belldandy's attitude and love for humanity reminds her of the Almighty One and the relationship they once had. Because of this, she has often tried to corrupt or hurt Belldandy several times throughout the series. She also seems to have some feelings for Keiichi Morisato.
She appears a few times before leaving an avatar child version of herself, who would go on to become a regular antagonist for the goddesses, as well as a direct supervisor for Marller. While this avatar possesses only one thousandth of the true Hild's power, it is still enough to make the avatar a powerful enemy for anyone. In the manga, a small team of demons sealed her main body and attacked her avatar in the human world.
Lord of TerrorThe
Lord of Terror is a virus that runs on
Yggdrasil. It is divided into two parts - the will of the Lord of Terror, and the "Ultimate Destruction Program", Fenrir. It wants to destroy the world and create a world for demons in its place(this happens only in the anime, while in the manga we can see that his intent is to destroy the entire universe in order to create a new, violent one; this is the reason why Keiichi, possessed by the program, wants Skuld to build a 11 dimensional scythe for cutting the 11 dimensional string of the universe, which permit its existence). The heir to the Lord of Terror was Urd, because of her mixed ancestry. Basically, the Great Lord's will influenced Urd and eventually sealed her will away. It then utilized the urn Mao Za Haxon, which contained the Ultimate Destruction Program's bootup. After it had possessed Keiichi, Belldandy told it to transfer to her but it could not possess her and was quickly forced to transfer itself to a floppy disk and was then erased by Skuld with a magnet.