Jafar is a boss that is found in Kingdom Hearts, Kingdom Hearts Chain of Memories, Kingdom Hearts II, Kingdom Hearts Re:coded, and Kingdom Hearts Union χ. He is one of the bosses at Agrabah, and assumes a Genie form.
Kingdom Hearts coded
The all-powerful genie Jafar became by using the power of the magic lamp. He sought to conquer Agrabah, and with Iago at his side nearly triumped over Sora. In the end, though, he was imprisoned within his own lamp.
Having assumed the form of a gigantic genie, Jafar picks up massive fireballs to throw at the party. Sora can do damage with his new Blizzara spell, but it is wiser to aim for the lamp, which Iago carries around the room. Lock onto the lamp carried by Iago to attack it repeatedly. To avoid damage from Jafar's fireball attacks, use Dodge Roll, and cast Aero on Donald and Goofy. Alternatively, Sora may use Guard to fend off the fireball attacks. Jafar will also lean in and swipe at you if you're too close to him: striking his hand at this time will stun him for a few seconds. Upon victory, Fire is upgraded to Fira and Ansem Report 1 is obtained.
Kingdom Hearts Chain of Memories
Jafar uses the same moves as he does in Kingdom Hearts, but with more time in between attacks. Just as in the first game, attacking Jafar will not deal any damage: Sora has to hit Iago, who is carrying the lamp. As Sora cannot use Guard in this battle, it is best to Dodge Roll away from his fireballs, or break Jafar's cards. Keep any Sleights to use for the lamp. Like all other boss battles, heal when necessary.
In Reverse/Rebirth, keep the King Mickey card as the third card for a sleight if Riku's HP is running low and he cannot break Jafar's attacks. Also, the Maleficent enemy card can help, as it boosts Riku's strength without slowing down his reload speed (since Riku can reload his cards instantly). It is recommended to refrain from entering Dark Mode, as the auto-target will land on Jafar and Riku will attempt to attack him instead of the lamp.
Kingdom Hearts II
Sora fights Jafar in the sky above Agrabah. The entire field can be exploited to ones' advantage. However, one may be left at a disadvantage because Sora fights Jafar while flying around on the Carpet, and this might create some maneuverability issues. Beware of the buildings/debris that encircle Jafar—they deal substantial damage to Sora.
Jafar has several attacks in this battle—a fist swing, fireballs, lightning bolts (signified by Jafar saying "Cham Dabadabada"), pillars (only when he has the hand aura), and capturing and immobilizing Sora, making him unable to move (and invincible to the fist swing). All of these attacks can be guarded with Reflect magic.
Unlike previous battles against Jafar, Sora now attack him directly instead of attacking his lamp. Jafar has two weak points, notably the head and the torso. Depleting Jafar's torso health will leave him stunned and activate a Reaction Command that will allow Sora to spin Jafar around and stun him even longer. Attacking the head without stunning him first is possible, but not recommended, as Jafar will likely stun and repel Sora before he can perform any finishers to do real damage. Sora can also attack his hands, but it is quite dangerous.
Every now and then (usually when he snares Sora), Jafar will shift Sora to another dimension. Debris will be flung against Sora and if he does not guard himself against it, his HP will be greatly reduced. This can be avoided, however, by flying around (mainly in circles as well as up and down) constantly. Sora will get hit, but not as much as he would remaining idle. Sora can also completely avoid this part by casting Reflect when Jafar says, "You will never escape". Use physical attacks as much as possible, and heal when necessary.
Kingdom Hearts coded
Sora battles Jafar after entering the Keyhole in Episode 5 of Kingdom Hearts coded. Iago is also present during the fight and holds Jafar's lamp.
Kingdom Hearts Re:coded
In this battle, Data-Sora must again attack Iago who is holding the lamp, instead of Jafar. He is fought in two phases.
During the first phase of the battle, Iago will just fly around the arena while Jafar attacks Sora by throwing fireballs and "blinking" a purple orb. The fireball will deal major damage, so be prepared to dodge it. The purple ball can inflict Slow on Sora making moving around difficult, so be sure to block it. It'll hit Jafar instead and will make Iago Slow. Jafar will also summon two Bandits.
During the second phase of the battle, bug blox will appear around the arena, providing steppingstones needed for Data-Sora to reach Iago. Iago will be exhausted on the second phase and he will stay in one of the corners of the arena. Jump all the way above and strike him. If enough damage is dealt, he will fly at a high speed away from Sora. So he must chase Iago down to deal more damage. This time, Jafar won't use the purple orb nor summon any Bandits anymore. Instead, he uses a new attack in which he throws a fireball above, only to fall down to Data-Sora without warning. Be sure to heal when necessary.
Notes and references