The Three Knights, also known as The Three Dragoons, is the title given to those chosen by the gods to fight alongside humanity during the Ogre Battle.
Many times stronger than the average human, it was said that each blow from one of the knights could kill a dragon, and that they could even commune with, and tame dragons. The three knights consist of Slust the Red, Fenril the Ice, and Dragon Fang Fogel. During the final battle on the Kastolatian Sea, they pushed back the demons and personally sealed Galf, an underworld general in the land of Antanjyl. After the war, the three acended back to the heavens, and have not been heard from since.
Of the three, Fenril seems to hold the most love toward humanity. Despite the gods orders, she gave the holy sword Brynhildr to humans, in hopes that when evil arises again, one with the blessings of the gods could call upon them once more. After these events, it is said Fenril was imprisoned in Organa by the gods, and hasn't smiled once since.
The Three Knights live on three sky islands. Slust resides on Muspelm , Fenril on Organa , and Fogel on Shiguld. Revered by those that live with them, they are seen as heroes by many, and demigods by all.
Many years later, Rashidi found his way to their sky islands and charmed each one in turn. Destin Faroda broke them free of the mind control magic Rashidi had used on the them, and they joined the rebellion, once again fighting alongside humanity. After Rashidi had been defeated they returned to the sky islands once more.
Somewhere along the way, Slust seemed to develop feelings for Fenril, and is seen trying to woo her after the events of Ogre Battle: The March of the Black Queen. She replies in an embarassed tone, though it is not known if she accepted his feelings, or if it was just his reputation as a womanizer driving him.