Missing parents, and the girl left alone

A beautiful girl who travels dimensions to find her parents. She was an ordinary student who grew up with a lot of love and affection from her parents, but after her parents disappeared in an incident, she began to distrust people and darkness grew in her heart. Later, through a chance encounter with 'Dou', a shadow creature created to protect Charakter before her parents disappeared, she overcomes the darkness in her heart to some extent.