Gorou Amamiya

Gorou (ゴロー, Goro), born as Amemiya Gorou, is a character from Oshi no Ko manga. He is a doctor specializing in gynecology, and the one responsible for caring and delivering Ai Hoshino's baby. He is also Aquamarine Hoshino in the previous life.

Appearance
He is a man with jet black hair and square rimmed glasses. In all of his appearances, he always wore a doctor's white coat.

Story
Gorou worked his residency years on a hospital, located in the rural area of Miyazaki prefecture. He met Sarina during this time, a child patient affected with anaplastic astrocytoma, and he was introduced to her oshi, Ai Hoshino. They discuss about reincarnation, and share a cute moment, but later on it is revealed that she died, at the age of 12.

Four years later, Gorou became a doctor on the gynecology department the same hospital. He was caught watching on Ai's performance as a member of B-Komachi on a patient nurse by his nurse, and she informed him about the news of Ai's hiatus. She told the story about Sarina to the nurse, but she instead think of him as a pervert who uses sob story to justify his own obsession with Ai.

He then meet with another patient, a 20 weeks old pregnant teenage girl accompanied by an older man, her guardian. It was then revealed that the girl is Ai, and her guardian is her company president, Ichigo Saitou. Gorou battled over his feelings of a fan and moral obligation as a doctor, but then he had a conversation with Ai about her twin child and lies as a form of love, and her declaration to keep being an idol while having the twins secretly. He then assures his idol that he'll safely deliver them both, owning up his position as a fan.

They spent the next few weeks together, working on the process of keeping things secret and options for delivery that would not hinder her career, before she decided to do it naturally. The night of the due date, Gorou was approached by someone who knew about Ai's pregnancy and his role in it. He chases him away to a mountain trail, but then was murdered.

He then reincarnated into Aquamarine Hoshino, who were born that night along with his sister Ruby Hoshino.

Later on, a personification of Aqua's guilt over Ai's death manifested as Gorou, who lambasted him over his inability to save her.

During Aqua's trip to Miyazaki, more of Gorou's past is revealed. His mother died shortly after birthing him on her own due to postpartum hemorrhage, because she hid her pregnancy from her parents. Without knowing who his father is, Gorou was sent to the care of his grandparents. Due to the circumstance, Gorou decided to enter medical school to became a surgeon, but instead became a gynecologist because his grandmother thought he wanted to be because of how his mother died.

It was also revealed that Gorou was there when Sarina was close to death, with Sarina making him promise to take care of her Ai Hoshino keychain she got in a B-Komachi concert when she was well, treating it as if it was her. He also hears Sarina's confession of love, and how she hopes she can be reborn, presumably so in the next life that she can be with him, but she died before finishing her words.

Trivia

 * Both Gorou and Sarina are the only characters that were introduced without a surname, all the way until Chapter 75, where their surnames are both revealed.