User blog comment:Xilinoc/Ch. 555 - THE HERO/@comment-9096222-20131031131841/@comment-26420452-20131031181229

She said "So you can use the Vollständig (now)?" (now being present only in the Mangastream scanlation). This implies that Giselle didn't know that her comrade, another Sternritter, could use it. Apparently, it's not mandatory to be able to use Vollständig in order to become a Sternritter. Whether there really are Sternritters who can't use it is another thing.