He is a giant suit of armor.
He was a cold cruel merciless tyrant who ruled Agrabah with an iron fist. He had no mercy for others and was a master manipulator, often pretending to be the Sultan to trick Aladdin and Jasmine into letting their guards down. He was also power hungry and greedy, willing to wage war against others and was extremely paranoid and hot tempered. He was also very arrogant, believing strongly in his strength and was easily offended at what he perceives to be the slightest offense.
Role in the episode
When Dominus Tusk was terrorizing the city of Agrabah destroying buildings, easily taking care of the city's army and defeating Jasmine, The Sultan it took upon himself to stop the giant minotaur from devastating the entire city by donning the invincible Armor of Kileem, an evil ancestor of his family. Shortly after this, Sultan had Dominus Tusk outmatched in speed and strength. After an intense battle, Tusk's horns were mounted on the wall in the Sultan's newly refurbished throne room, so revealing that he was killed by the Sultan, who was being possessed by the evil spirit of Kileem. Slowly Kileem takes over the Sultan’s thoughts making the poor man plan an invasion of all the other kingdoms of the seven deserts making them part of Agrabah.
In attempt to restore the Sultan back to normal, Aladdin devises a plan to force him to remove the armor. He lures Kileem to a cliff side high above a river and Genie pushes him into the river. Aladdin’s plan seem to have worked, though unknown to everyone, Kileem digs a tunnel back to shore then gets his revenge. He knocks the gang out and has the guards arrest Jasmine for treason.
Now that Kileem has taken over the Sultan's thoughts he is prepared to execute Jasmine. Just in time Aladdin saves her and challenges Kileem before he discovers the statue is the source of the spirit's power. Kileem storms at our hero seconds before impact, and Aladdin jumps away causing Kileem to destroy his statue releasing the Sultan from his grasp. His spirit then emerges from the broken statue, then explodes into oblivion.