Yuuta Asuka

Manager of the boys’ soft tennis club. They are the younger sibling of Izumi and Hikari Asuka.

Their sisters and Maki call them a more gender-neutral “Yuu”. Unbeknownst to Touma, Yuu has a crush on him. Yuu is revealed to be non-binary and questioning their gender in episode 8. (Source: Stars Align Wiki)