Yumiko Hino is the older sister of Maya Tōmi, with family ties to the medical field through their mother Chizuru, the sole doctor on Tatsumiya Island. Yumiko serves as a teacher for the handicapped, contributing to community education and care.

In the sequel *The Beyond*, an antagonist named Serenoa appears with Yumiko Hino's identical physical likeness. Serenoa aligns with Festum swarms and Marespero, participating in assaults on Tatsumiyajima and Wadatsumijima. She demonstrates assimilation abilities and controls Festum during battles, operating alongside Legato and Floro while coordinating swarm attacks. Serenoa attempts to assimilate pilots such as Rina Nishio and Maya Tōmi, succeeding in assimilating Maya's right eye. She pursues goals to bring others under Marespero's control, expressing surprise at unexpected resistance like Rina Nishio's self-sacrificing tactics and fear when confronted by annihilation from weapons like the Mark Alles. Serenoa also manipulates targets by assuming familiar forms, such as appearing as Miwa Hino's deceased mother during an assault on Alvis' L-Boat to target Miwa's consciousness.

This appropriation of Yumiko Hino's likeness represents a deliberate use by an antagonistic entity, separate from Yumiko's established role as an educator.