Why Did Chiyuki Kill Herself?

In case you forgot Chiyuki's backstory, she's a talented ice-skater with a passion for it, but one day she sustains a knee injury and she can never skate again. Falling into a state of depression, she commits suicide.

Why did Chiyuki commit suicide?

Chiyuki brought to light the idea that the extreme conditions were creating darkness in the hearts of the souls instead of drawing them out. Later, Decim shows great interest in learning more about Chiyuki's background. When the time comes for him to finally make a judgement on her, the two end up embracing in sadness.

Did Chiyuki get reincarnated?

She was sent to reincarnation represented by the sign above the elevator. One sitting on the chair is a mannequin it has no eye balls. Firstly, in episode 11, in Ginti's bar, when he sent Harada and that girl, it was shown to be the reincarnation mask, but soon enough it changed to the void mask.