User blog comment:IamJakuhoRaikoben/Chapter 422: Orochi's Fin, Review./@comment-5268982-20150302165932/@comment-25111584-20150302204712

She said it's Celestial Spirit Magic.

She was shown to use the key to equip that dress. It might just have been a gesture, but unless we see her equipping it without using the keys, that panel is all we have to go by.

From the info we have, definitely holder as far as I'm concerned. ._.