Kain Highwind (カイン・ハイウィンド Kain Haiwindo?, "Cain Highwind" in the Japanese version) is the leader of the Dragoon Knights of Baron as well as childhood friend of both Cecil and Rosa. He claims that being a dragoon makes him feel closer to his father, who died when he was very young. Although best friends with Cecil, Kain is in love with Rosa and must deal with his jealousy throughout the story. Like Cecil, Kain notices the King of Baron's unusually harsh behavior, but he is under the mind-control of Golbez, and thus becomes Cecil's enemy. Kain eventually breaks free of Golbez's control after Tellah weakens Golbez. At this point, Kain joins Cecil's group in their efforts to defeat Golbez. However, after Cecil claims the last Dark Crystal, Golbez resumes his control of Kain. When Zemus' mind-control of Golbez breaks, Kain is released and helps Cecil's group destroy Zemus. After the final battle Kain is overcome with remorse for his actions, and decides that he must atone on Mt. Ordeals before he can rejoin his friends permanently.

At the end of Interlude, Kain, who is still living on Mt. Ordeals hears a mysterious voice calling to him. He reappears in The After Years as the "Hooded Man" (謎の男 Nazo no Otoko?), assisting Ceodore, while hiding his real identity.[23] He is impersonated by the incarnation of his negative emotions, Dark Kain (ダークカイン Daaku Kain?), who wishes to kill Cecil and have Rosa for himself. Kain defeats his dark alter-ego and merges with him, causing Kain to become a Holy Dragoon. After helping his friends to defeat The Creator, Kain returns to Baron to assume command of the Red Wings.

Kain has also been featured in Dissidia 012 Final Fantasy as a playable character, as producer Tetsuya Nomura wished to add him to the fighting game. He is voiced by Kōichi Yamadera in Japanese and Liam O'Brien in English.