Guardian Hearts

Guardian Hearts (がぁーでぃあんHearts) is a romantic comedy manga, created by Sae Amatsu, which was released in 2001. It belongs to the "harem" type of manga where one boy is romantically pursued by several girls. What is unusual for this series is that each girl has a different origin and motivation, as opposed to all being of the same or similar type.

An OVA series was released in 2003, with three sets of episodes. Two years later, a new OVA series was released, named "Guardian Hearts - Power Up". The first series was mainly comedic; the second series was violent and more serious but also had elements of comedy.

Brief summary
A guardian heart by the name of Hina accidentally reveals herself to a boy. The two then begin living together. As the story progresses, more girls begin living with them for the same reason.

Characters
Seiyū: Takahiro Sakurai
 * Watari Kazuya

The male character of the show. The ever so lucky or perhaps unlucky guy who discovers the identities and secrets of different kinds of girls throughout the series and ends up with living with all of them. In the beginning, he discovered the identity of Guardian Hearts Hina, and so to keep it secret he had no choice but to let her live with him. The rest is the same for all of the girls who followed afterwards.

Seiyū: Rie Kugimiya
 * Hina

One of the main female characters. Her secret identity is that she is actually a Guardian Heart, the protector of peace and well-being of Earth. However she must always keep her identity a secret, but it ended in failure just as she arrived at Earth when a high school boy named Kazuya saw the entire thing. She asked him to live together with her, and become "family" so her secret identity would be kept secret. She also has to complete tests given by her superior so that she can stay on Earth. She likes Kazuya and pushes the other girls away when they're getting close to him.

Seiyū: Haruna Ikezawa
 * Chelsea

One of the main female characters. She is actually a princess from a magical world who came to earth looking for a husband. She also hides a secret identity which is that she is a magical girl. Her accidental meeting with Kazuya became her resolve that he was fated to become her husband, especially since Kazuya found out her true identity. She is very obsessed with Kazuya, by constantly daydreaming about him and hates Hina for always getting in her way (which she doesn't know is the guardian heart). She hates the guardian heart for always disturbing her from getting close to Kazuya.

Seiyū: Kae Araki
 * Maya

One of the main female characters. She is known as "Black Maya" from her ninja clan. She is a runaway ninja (reasons are unknown), but still acknowledges herself as a ninja from her clan and upholds the traditions of her clan. One of the traditions is to keep their identity secret, or else they must kill the one that knows their identity. Kazuya found out about her identity when he came across her ninja tools. As she commence combat with the Hina as a Guardian Heart protecting Kazuya from Maya, Kazuya helped Maya escaped. Thus she owes him, and as one of the traditions, she must pay the favor back, and so she also lives together with him. She hates Kazuya in the beginning, especially when she had no choice but to become his wife because he saw her naked twice (as well as being kissed twice by him) which is one of the ninja traditions. However throughout the show, she later warmed up to him when she realizes he is reliable and kind, she constantly thinks that Kazuya is fated to be her husband, and in the end she accepted Kazuya to be her husband but still cannot express her feelings well. She hates the guardian heart as well for beating her in a fight.

Seiyū: Kyouku Tsuruno
 * Kurusu

One of the main female characters. Kurusu is an alien and came from a planet where her tribe has the power to use the skills and powers shown by the clothes she is wearing ( mostly uniforms ), and so she is known to always wear cosplay. She apparently loves Kazuya at the start, since she confessed her identity to him, but their conversation was interrupted by guardian heart. She also hates the guardian heart for interrupting her from confessing to Kazuya. She also lives with Kazuya.

Seiyū: Hisayo Mochizuki
 * Kotona

One of the female characters that lives together with Kazuya. She is a miko (priestess) from the planet Karutei, and so she can sense spiritual power and also exorcises spirits. Her reason for staying with Kazuya is unknown, but she apparently lives with him when the rest of the girls starting living with him as well. She loves food and loves to eat, and can withstand those that are deadly to humans.

Seiyū: Mayumi Shintani
 * Daisy

A female talking cat who started living together with Kazuya as well, but is more close to his mother. She gets along with Kazuya and the rest, except Chelsea which for some reason she started teasing even before she started living with Kazuya. She encourages all of the girls except Chelsea in getting close to Kazuya. When her ear is pulled three times she turns into a big monster which just looks like a Godzilla-sized white cat.

A yellow bird, who can transform into a girl, and is living with Kazuya. Her identity is unknown, but she apparently is also a power that can make Kazuya transform into a heroic figure. She is the only character who cares for everyones wellbeing and doesn't take sides. She is also the narrator in the series.
 * Tori

Themes

 * Opening theme: Nagareboshi no hi by Sleepin' Johnny Fish
 * Ending theme: Glassdama by Sleepin' Johnny Fish