Complex sentence: As they are traveling Jermayan teaches Kellen how to become a knight when he learns that Kellen is a knight-mage, making him an excellent fighter, but only an average wild mage.
Split into simpler sentences: As they are traveling Jermayan teaches Kellen how to become a knight when he teaches him he learns that Kellen is a knight-mage. Which makes him an excellent fighter, but only an average wild mage.