"Mou.... Hatarakitakunaindesu" Boukensha Nanka Yamete yaru. Imasara, Taiguu wo Kaerukara to Onegai sarete mo Okotowaridesu. Boku wa Zettai Hatarakima…

[MangaDex]

 

[NicholasTurner]

So they know he's a magician but not what his unique specialty is. Any magician can cast buffs or do any of these spells like Aix but Aix is the only one who can cast them for so long.