The members of Oh My Girl are ordinary friends, but the only one who is not an ordinary person is Arin. In fact, Arin was a victim of a mysterious incident in the past and her body became light, so she was able to move at high speeds at some point. However, she did not want to reveal that she was a victim, so she hid it. The incident happened without anyone knowing, and in the end, she revealed that she was a person with abilities and disappeared.
