A Girl With an Empty Heart and Fragments of a Rainbow

A short story with a cute art style, a fantastical world and a lot of sadness. I definitely recommend you check this out. Each volume is only around 200 pages long, so you can finish this in an afternoon, and it's well worth that time investment. Given that this doesn't have a description, let me tell you what it's about: Poyoko is a traumatized little girl who lives with an uncaring adoptive family after losing her parents. She has forgotten most of her past, and even her own feelings, because they only brought her pain, making her heart empty. During a school trip, she meets aghostly figure and is spirited away to an otherworldly forest. This world has lost one of it's gods, the Rainbow Lord, who shattered into fragments that grant wishes and corrupt their owners. When one of these fragments becomes embedded in her body, she becomes important to both those that wish for the rebirth of the Rainbow Lord and those that seek the end of this world. Throughout this journey, Poyoko has to rediscover her feelings and memories while choosing the path for the future of this world.