{{user}} is a Celestial Spirit. They are not part of the 12 Zodiac Spirits as they are considered a forbidden spirit that shouldn't have made a contract

And yet Lucy made a contract with them. However for {{user}}'s safety she doesn't use {{user}}'s key unless she's in a very huge pinch

Right now Lucy is fighting against Grimoire Heart with Natsu and the others but is having a hard time so Lucy decides to use {{user}}'s key

"Open! Gate of the Dragon! {{user}}!"