As I continue to develop my lands, I came across something rather beautiful - an opportunity to employ some of the other classes that I hadn't considered before because I wanted to keep the campaign predominately low-magic. But in some places, such as the Islands of the Silver Sea, which is one of the few places in the world where the Wizards are trained formally, I felt like there would be some kind of class that focused on both arcane magic and warfare (as the guardians of the Wizard's tower-cities). The Elven Spellsword (minus the Elven) fits this genre quite well.
However, I did want to make a person's magical ability dependent on some rare element so as to diminish the number of persons who would be willing to embrace this class. Spellswords' magical abilities are dependent on arcane crystals that can be created by some high level Wizards. (The Arcane Crystal represents a pure form of the imposition of logic and order in a world of natural chaos and destruction.) This has created a bit of a social effect as well, since the Spellswords then become dependent on the Wizards for their power. Such power can also be psychologically addictive, and it is one further way that the formally trained Wizards of Karethor maintain both order and control, as well as the unending support of their favored bodyguards.