Fanny Moriyama, also known as Fanni Moriyama, is the biological son of Shinsuke and Shizuko Mine. Financial hardship led his parents to place him for adoption early in life, hoping to secure him a better future. As a young adult, he reconnected with the Mine family, forming a close bond with Nozomi Mine and developing romantic feelings for her. Despite his imposing physical stature often described as a Gentle Giant, Fanny exhibits a consistently kind and supportive nature.

His relationship with Nozomi shattered when Michiko, the nurse who swapped Nozomi and Miki at birth, falsely declared them biological siblings. Horrified and seeking to shield Nozomi from pain, Fanny abruptly ended their relationship and left for America. This departure coincided with Shinsuke’s declining health and death; Fanny missed his biological father’s final moments, later honoring Shinsuke’s memory through a beer libation ritual at the family altar.

After Michiko’s deception and the baby-switch truth emerged, Fanny reconciled with Nozomi. Their romance rekindled, leading to an engagement in the manga continuity. However, their story diverges sharply across adaptations: the manga depicts Michiko deliberately causing a car crash to block emergency aid when Fanny contracts tetanus, resulting in his death. The anime spares him, allowing the couple to affirm their commitment.

Raised separately from the Mines, Fanny displayed unwavering loyalty upon reuniting with them. He unknowingly donated blood to his biological father Shinsuke during a hospitalization, unaware of their connection. His arc intertwines with the family’s major revelations and tragedies, supporting Nozomi through grief and identity crises while navigating his own misplaced guilt and familial discoveries.