TV-Series
Description
En Yufuin, a third-year student at Binan High School, champions laziness and minimal effort under his self-proclaimed "ultimate negligence doctrine." As a founding member of the unofficial Earth Defense Club, he claims a club room labeled as such. His days revolve around sleeping late, gaming, and snacking on onsen manjuu, embodying his laid-back existence. Despite this aversion to exertion, he wields sharp deadpan wit and openly voices annoyance when forced into action.

His deep bond with fellow club member Atsushi Kinugawa began in middle school when En stopped Atsushi from tripping. Their contrasting personalities—En’s lethargy versus Atsushi’s diligence—forged an interdependent connection often humorously likened to a "married couple" dynamic. En describes Atsushi as essential "like air," privately acknowledging him as irreplaceable "oxygen." This relationship strained Atsushi’s childhood friendship with rival Kinshiro Kusatsu. Within the official otome game, En admits romantic feelings for Atsushi in one storyline, seeking guidance on same-sex attraction.

After encountering a spacefaring wombat-like creature, En gains supernatural abilities. Using a "Loveracelet," he transforms into **Battle Lover Cerulean**, the "Flashing Prince," themed blue to represent water-based powers. His weapon, the **Purifying Aqua** love stick, unleashes attacks like **Cerulean Aqua**. He initially resists this role, questioning why he must fight despite lacking motivation, yet participates to protect his companions. His battles frequently oppose the Earth Conquest Club, led by Kinshiro under the influence of Zundar, a hedgehog-like alien spreading negativity.

Throughout the series, En’s development remains anchored in his dislike of effort. He relies on Atsushi for daily routines like waking up and meals, sharing downtime in cafés or parks. Though he openly grumbles about Defense Club duties, he concedes his friends make life "not so bad." His commitment surfaces in crises, like defending the school graduation ceremony against monsters in the OVA *LOVE! LOVE! LOVE!* where the club reflects on their journey. Here, En joins a final team battle against Zundar’s "Second Button Monster," showcasing reluctant yet steadfast loyalty.

En’s philosophy persists across all media: he declares idleness "the key to peace" yet subtly values the camaraderie forged through conflict. His story concludes with graduation, ending his active Defense Club role while his core identity remains unchanged.