Sachi

 Sachi
 Reborned legend.

 Sachi is her parents middle child. Her mother was a dragon and her father was a fox. Seeing her born without any dragon features, parents belived she's the first naturaly born Cerberus. To their misfortune Sachi never showed any ability to use magic. 

 She was lucky to be noticed and reborn as a Fox Demon. Rulers of the realm got quickly interested in her, cause she doesn't have any standout appearance features common for Fox Demons. It turned out that she indeed was born as a Cerberus, but due to her body not being able to store magic, some genes never were active. After becoming a magical creature, she can finally use her intended powers. Although she has only two tails her power can be compred to Winas.