Kyoukai Senjou no Rinbo

From Fairgame:

Fuu is a girl who was born as an elf/human hybrid, which caused her to be unwanted by either side. Fuu leaves her hometown and arrives at a place called “Limbo”, a world where hybrids like Fuu gather. Day by day, Fuu’s interactions with the residents of Limbo let her heart and feelings grow bit by bit.