Best Ecchi Anime of 2003

In the Kanto region, seven high schools are locked in a deadly struggle for total dominance. Each combatant is the reincarnation of a famed warrior from the Three Kingdoms era, forcing them into a dangerous quest to overcome their often merciless fates. Among these fighters is the scatterbrained Hakufu Sonsaku, a student at Nanyou Academy who—despite having superb martial arts skills—is fated to die young at the hands of the ruthless Ukitsu. But her classmate and cousin, Koukin Shuuyu, is entrusted by Hakufu's mother with protecting her from this dark destiny. To complicate matters, Hakufu experiences sudden fits of rage during which she loses consciousness and unleashes a devastating power that endangers her own life. Alongside Nanyou's "Big Four," Hakufu and Shuuyu must thwart the schemes of their chief rival schools and discover the real nature of Hakufu's abilities before time runs out.

Kanenone Gakuen is a boarding school for boys situated in rural Japan. While single-sex education is common, the lack of female students in the surrounding area creates significant social challenges. To support the mental well-being of the students, the administration plans to merge with a nearby all-girls school to establish a co-ed institution. The male students are eager about this change, while the girls are intrigued by the prospect of a more dynamic campus life. As a preliminary step, the girls are invited to reside at Kanenone for a month to test the arrangement. The story centers on Yuusuke Takazaki and his roommates, known as the Baka Trio, who pride themselves on their ability to interact with girls without appearing foolish. However, the arrival of the female students brings chaos, hormonal tension, and absurdity. Midori Chitose, one of the new arrivals, jumps off the bus and immediately hugs a bewildered Yuusuke. This sudden affection raises questions about whether Yuusuke is naturally charming or if he shares a forgotten past with her.

In the universe of Maburaho, every person is born with magical abilities, making them magicians. But magical capacity differs from one individual to another. The number of times you can cast spells dictates the level of esteem you earn, and because magical power is fixed from birth through lineage and heredity, those descended from renowned magicians are highly coveted. At Aoi Academy, Kazuki Shikimori possesses the lowest magic count, causing his peers to regard him as a nearly useless magician. Yet his ancestry includes numerous legendary magicians across history, meaning that while he may not be powerful himself, his future children could be. This makes him a target for three different young women: Yuna Miyama, a transfer student who immediately claims to be his wife; Rin Kamishiro, a proud swordswoman from a traditional family who wishes to kill him so she can follow her own path; and Kuriko Kazetsubaki, a girl from an influential clan who openly tries to seduce him for his genetic potential. Now he must cope not only with the envy of every male student at school, but also with the relentless pursuit of multiple women.

Battle Programmer Shirase, or BPS, is a freelance programmer possessing extraordinary hacking skills who refuses to work for monetary compensation. Instead, he accepts payment only in forms that appeal to a peculiar few like himself. Despite his unassuming attitude, the jobs he ends up taking are far from ordinary. When the nefarious King of America stirs up chaos online, Shirase finds himself constantly occupied, and each fresh mission introduces an ever more colorful cast of characters into his life.

Hatsuki, a high school student harboring intense romantic feelings for her sister Hatsumi, witnesses Hatsumi vanish in a flash of green light on her sixteenth birthday. Guided by a creature that looks like a plump baby chick, Hatsuki tracks her sister to the Great Library, a realm containing various worlds preserved within books. Finding Hatsumi absent, Hatsuki embarks on a journey across different books to find her beloved sister.

The sisters Ai, Mai, and Mii, along with their android maid Mea and a slippery pet ferret named Unagi, journey through time and space while keeping their beloved mansion with them. Guided by clues from strange dandelion-like plants called Popotan, they seek someone who can answer their most personal questions, yet they still find time for side trips, meeting new friends, visiting hot springs, and occasionally running the X-mas shop kept inside their house. However, their ultimate destiny holds many surprises, and not every moment is cheerful—moving through time forces them to leave friends behind.

Five years ago, Goh Saruwatari, the pilot of Dannar, first encountered Anna Aoi while battling an alien force called the "Mimesis." Now, on their wedding day, the ceremony is disrupted when the Mimesis launch another attack. While Goh struggles against the alien threat, Anna discovers a top-secret robot named the "Neo-Okusaer" and deploys it as a last resort to save her fiancé. At that moment, Dannar and Neo-Okusaer combine to form the colossal robot "Godannar."

Teacher Sorata Muon carries on his family's centuries-old tradition of being the master thief Mouse, capable of stealing anything after properly notifying authorities of his intentions so they can be present yet fail to stop him. He is aided by three nubile female assistants who also use the teaching cover and, in typical Satoru Akahori fashion, favor tight, skimpy, or bondage outfits over their ample curves as they constantly pursue Sorata far more than he pursues them, though the girls do receive some attention from their master. Not only is Mouse chased by the girls and local law enforcement, but a secret art protection society also employs a former ally of Sorata's to go after his pretty little hide—all in 15-minute episodes.

Around the 37th year of the Meiji Era (1904), during the Russo-Japanese War, the outnumbered Japanese army relies on a special flying ship called the Amanohara, powered by a benevolent demon, to launch an assault on Russia's key stronghold at Port Arthur (Lushun). Umakai Shintaro, a Japanese-born Russian diplomat, defects and travels to Sapporo to teach at a girls' academy. But this academy is far from ordinary—it is located aboard the Amanohara, and the five girls Shintaro instruct form the Raimu Unit, each possessing the ability to summon powerful beings to fight on their behalf. Shintaro soon becomes both their teacher and battlefield commander, and together the six embark on a bizarre and highly erotic journey. As Shintaro helps the girls overcome their weaknesses, grow stronger for the final battle at Lushun, and unravel the motives behind the opposing "Russian Spiritual Corps," he discovers that among its members is someone he once knew well.