I am the heroine's godfather!

Transmigrating to another world and awakening his memories, Loran initially thought it would be a typical overpowered protagonist story, only to find himself kidnapped and sold into a military camp? Luckily, he met an older brother in the camp who offered him considerable help. After a battle, Loran chose to retire, while his older brother chose to stay in the military. Although they maintained correspondence, they didn't see each other for many years. Loran then spent several years as an adventurer, making some friends, finding his family, and eventually opening a humble magical item shop in the capital of a certain country. As for his past, it was best left unsaid. He received news again when his older brother's daughter arrived with a letter. Seeing this orphan of his older brother, Loran ultimately decided to adopt her. It was at this moment that Loran's long-awaited cheat code finally arrived. The system called itself a "nurturing system," claiming that his older brother's daughter was actually the heroine of a third-rate isekai novel. Loran could receive generous rewards by nurturing the heroine. To deal with the hidden disaster, Loran accepted the system, intending to raise his older brother's daughter into an outstanding young woman. And that male lead, stay away from my daughter! But as the plot unfolds, some of Loran's past romantic entanglements come back to haunt him, and his daughter's gaze towards him begins to look strange.