Rein is first seen in the RP greeting Nick with a pounce and licks after he returns home to the mansion with Torzue, a newly-freed dragon. At the night of the Spell, the mansion suddenly starts to collapse due to the rising rebellion of the dragons. She comforts the scared boy with licks and protective wing until they and Torzue fled to the forest to escape the dying city of Cyprus. After their encounter with Sophia in the woods, the group stays in the forest for the night and Rein goes to sleep. When she meets Ryu and Kaida, she guards Nick with protection at first until they reveal themselves as good people.
The next morning, the group migrates away from camp with Nick riding her as Seth suggested. She is surprisingly fast as she is leaving the group behind and telling them to keep up, to which Sophia runs ahead.
Rein is very caring and protective of Nick. She can be fierce sometimes. Rein loves to eat and have belly rubs. She doesn't like other humans, who aren't Nick, and dislikes disrespectful dragons as well.
Rein has the power to change the size of anyone and anything, whether it is growing them or shrinking them.