"Poor Ritsuko, poor Reiko."

- Ryōhei Mikami

Ryōhei Mikami (三上 亮平, Mikami Ryōhei) is Tamie's husband, the father of Reiko and Ritsuko, Yōsuke's father-in-law, and Kōichi's grandfather.

Ryōhei has short gray hair. His eyes are always closed, so his eye color is never seen. In his younger days, a photo showed that he had black eyes.

Ryōhei is usually seen kneeling at Ritsuko Sakakibara's altar. He was emotionally unstable after Ritsuko and Reiko Mikami's deaths. During his younger years, he is shown to be a strict father. He doesn't allow Reiko to enter the art university. He is shown to be quite clueless about the current situation. It is revealed that he was still affected by Ritsuko and later Reiko's funerals.

Ryōhei made his debut in Episode 1, standing at Ritsuko's altar, saying that he is sick of funerals. On Kōichi's first day at his new school, he thinks Kōichi is going to the hospital. In the manga, Tamie said that after Reiko died, Ryōhei bought a bird and named it "Rei", which shares a similar pronunciation with Reiko. Though he knows about Reiko's death, his memory has not been altered by the calamity.