As with all the FFIV characters, little is known about Kain's background. Kain Highwind is one of the Dragoons, or Dragon Knights, in the service of the king of Baron. In the Japanese version of the game, it was mentioned that his father was also a Dragoon, and he is trying to follow in his father's footsteps. (Other family members are never mentioned at all.) The king, however, wants him to become a Dark Knight like his best friend, Cecil. Another thing that was left out of the American version was an apparent subplot in which Valvalis, Fiend of the Air, had a crush on Kain during the time he spent with Golbez.

   Though he calls Cecil a friend, he's actually very jealous of him, apparently because of Cecil's relationship with Rosa. During the course of the game, the jealousy in his heart allows Golbez to control his mind and use him as a tool for evil, even to the point of kidnapping Rosa to use as bait for Cecil. He seems to want Rosa all to himself, as evidenced by his line to her, "I'll show you I'm better than your sweet Cecil!" However, for some reason he doesn't have a problem with Golbez putting Rosa in mortal danger, when Golbez rigs a giant metal ball to crush her after a certain amount of time (or a blade to chop her in two, if you're playing the Japanese version). This seems to indicate he may not love Rosa in the way he thinks he does.