[Sombre]

Because it's a summon you mean? It's fairly easy to explain.

"When Teclis brought magic to the humans of the Old World, he knew that while too short-lived to understand High Magic and the full truth of the eight Lores, human wizards could certainly master one Lore. He founded the Eight Colleges that stand today; Bright, Gold, Grey, Amber, Celestial, Light, Jade and Amethyst. The Colleges pick only wizards of clear potential to join their ranks and while they compete for the best and the brightest, they work together to license and thus control aspiring wizards. These minor mages, known as Initiates, may be employed by any of the Colleges to fill lesser roles, acting as scribes, investigating rumours of magical sites and the like. For ambitious Counts and generals, Initiates serve as both magical support and contacts through which fully fledged wizards from their patron College may be hired."

A summon doesn't have to mean you draw a magic circle and use gems to make something appear. You can even have 0 gem summons which then cost gold.