TV-Series
Description
Kokeru Moroboshi emerges as the potential future son of Ataru Moroboshi and Shinobu Miyake, appearing exclusively in time travel or alternate future scenarios. His first chronological encounter occurs during a malfunction of Lum's space-bridging technology, which sends Ataru and Lum to 1991. There, the young Kokeru snatches Ataru's lunch. Ataru reacts with hostility while Lum treats the child kindly. Kokeru reveals his name, leading Ataru to deduce their familial connection through the shared surname. Lum observes Kokeru lacks horns, confirming he is not her biological child. Attempting to identify Kokeru's mother, Ataru takes him to a Tomobiki High class reunion. At the reunion, Kokeru exhibits poor bladder control and accidentally urinates on Ataru. He approaches an unrelated woman before Shinobu—visibly matured—claims him as her son. Before Ataru fully processes this, Lum returns them to their original timeline.

Kokeru reappears in the "Room of Destiny" arc when Ataru, Shinobu, and Lum explore possible futures using a key dropped by Inaba. Shinobu independently encounters an older version of herself accompanied by Kokeru. She witnesses this alternate Shinobu scolding Kokeru after he lifts a young girl's skirt, demonstrating his early emergence of inappropriate behavior mirroring Ataru. This version escorts Kokeru to the Moroboshi household, interacting with aged versions of Ataru's parents. Inaba later clarifies this is merely one fabricated potential timeline by the Destiny Production Management Bureau, not an inevitable outcome.

A non-canonical depiction occurs in a nightmare sequence experienced by Ataru's mother. This version presents Kokeru as the biological child of Ataru and Lum, diverging from his established origin.

Approximately four years old, Kokeru displays limited personality traits: a fondness for food, readiness to approach women, struggles with bladder control, and an inability to reliably identify his mother. Multiple characters note his strong physical and behavioral resemblance to Ataru's childhood self, particularly his early perverse tendencies like groping Lum's chest (manga) and skirt-lifting. His name serves as a deliberate pun: "Ataru" translates as "to hit," while "Kokeru" means "to fall."

Narratively, Kokeru embodies the series' initial trajectory where Shinobu was intended as Ataru's primary romantic partner. Creator Rumiko Takahashi conceived him to signify a future where Lum permanently departed Earth, leaving Ataru and Shinobu married. This direction shifted due to Lum's overwhelming popularity after her reintroduction in Chapter 3, prompting Takahashi to reposition Lum as the female lead. Consequently, Kokeru's original timeline was reframed as non-canonical within the "Room of Destiny" arc.