Onii-chan" wa, Mou Yameru - Hatsukoi no Otonari-san to Fukenzen Junai

After her father abandoned the family during her elementary school years, Hikari Shinomiya lived with her mother, striving to appear strong to shield her from worry. Her profound loneliness was alleviated by Noah, a half-Japanese boy from next door, who promised to act as her older brother. Throughout their school years, Hikari remained constantly by Noah’s side, sharing a closeness that often blurred boundaries, yet she remained uncertain whether he truly viewed her only as a little sister. Upon entering university, Hikari’s life took an unexpected turn when her mother and Noah’s father officially married. While initially delighted by the union, Hikari was shocked to find herself and Noah becoming siblings in both name and reality. However, the dynamic between them shifted dramatically as Noah’s physical affection grew increasingly intense. The situation escalated when he finally kissed her on the lips, deepening the encounter with his tongue, leaving Hikari to confront feelings that no longer fit within the bounds of a sibling relationship.