Editing Kain Highwind

In ''Final Fantasy IV'', after Cecil returns from a mission in Mysidia, the [[King of Baron]] sends him and Kain on a mission to deliver the [[Carnelian Signet]] to [[Mist (location)|Mist]]. Both Cecil and Kain notice an unusual air about the king. When the two reach Mist, the ring sets the entire town on fire. The summoner [[Rydia]] becomes angry and uses her [[summon]] magic to create an earthquake in her battle with the two heroes. Rydia soon warms up to Cecil, when they realize the king is trying to conquer the world, and destroyed Mist, thinking it was a threat. The earthquake, however, separated Cecil and Rydia from Kain (though it is up to the player whether Kain is hit by the earthquake or not, as he could be in the air thanks to his [[Jump]] ability).

When Cecil and Yang reach the [[Tower of Zot]] (this time with [[Cid Pollendina]] and the sage [[Tellah]] by their sides, instead of Rydia and Edward), Tellah gives his life using the [[Meteor]] spell to kill Golbez. Though Golbez is not killed, he is severely wounded. It is then discovered that Kain was under the control of Golbez. Kain regains his normal consciousness and frees Rosa. Cecil, Kain, Rosa, Cid, and Yang then face off against [[Barbariccia]], defeating her. He also reveals that he was somewhat conscious during his captive state, but wanted to keep Rosa near.

Kain remains with Cecil for quite awhile, trying to obtain the four Light and four Dark Crystals. However, before departing for the moon, Kain is re-taken control of by [[Zemus]]. [[Fusoya]] joins Cecil, and they defeat the Four Fiends inside the [[Giant of Babil]]. Kain then, once again, rejoins Cecil to defeat Zemus. He is also one of the few friends of Cecil not attending Cecil's wedding to Rosa. In the end he is seen at the peak of [[Mt. Ordeals]] with his hair blowing in the wind, vowing to become a great dragoon like his father. In the game's reissues and [[Final Fantasy IV (3D remake)|3D remake]], this is expanded on inside the extra dungeon, the [[Lunar Ruins]].  

Inside Kain's Trial, it is shown that after the outcome of the battle with [[Zeromus]], Kain enters the same mirrored chamber atop Mount Ordeals that Cecil used to become a Paladin. There, he is put into a scenario where Cecil, Rosa, and himself are at Baron. Kain wakes up lying on the ground, remembering only that he has been attacked by an unknown person. Cecil finds him and tells him there has been a murder. The victim is discovered to have been killed by a lance, quite obviously used by Dragoons. But Kain is discounted as a suspect, because he too was seemingly attacked, and knocked out by this person.

Eventually, it is revealed that the dark side of Kain who was killing the citizens of Baron, and this opposite Kain tries to force the real one to kill Cecil, knowing that he is the one who stole Rosa away from him. From that point, Kain must make a choice to whether kill Cecil or not. If the player chooses to kill Cecil, Kain fails his trial and does not receive his best equipment. If he chooses to spare Cecil, a boss battle with Lunar Bahamut results.  When Kain wins, he finally copes with the fact that he is not the object of Rosa's affection, and learns to move on.