Otonashi Sorami

Subaru's younger step sister who is a first-year high school student. She loves aliens which often annoys Subaru. Her favorite food is space food, and thus, she often makes it for Subaru, whether it be for breakfast or lunch. She is also a member of the UFO Research Club, which only consists of her and Yuu.

Spoiler

Sorami is actually half-human, half-alien, and has the ability to read others' thoughts.