Once Upon a Time (He Was Seen as Cunning)
Jay was six. Seven? Maybe five. And he was costly. Jafar couldn't afford to keep him anymore. So he rented him out, an item from his shop they could never steal because it would always come back. Until one day, when it didn't. He could remember that day so well. A purple-haired girl (Maleficent's spawn) had come to rent his finest stock. She had the money and all, so her mother must have commissioned her. but then, he saw his son run off with the girl, as if he knew her, and they ran off to Hell Hall, the home of that blasted Cruella de Vil, and his finest merchandise wasn't seen until a week later, when the Queen of the Isle threw him out of a window in her palace. Jay didn't eat for a month for his defiance, but he did bring home one of Cruella's coats, and from then on, when Jafar lent his son out, Jay had to come home with more than he started with, or he wasn't allowed inside. And when he was sent to a different school, in Auradon, Jafar went bankrupt. And when he betrayed his cause, no one would look at Jafar's stock, because for all it was worth, his son had been their one route off the Isle, and he had failed.
Except he hadn't.
Jay was better. He was stronger. Faster. Crueller. More hardened. More powerful than his father ever was. And Jafar hated it. His son, the only son he'd bothered to raise (there were a fair few others out there, and probably several daughters too, but they weren't Jay), whom he'd raised to be what he hated most, a street rat, so that he wouldn't think much of himself, had risen far beyond his anticipation. And then his plan had backfired. And his son, his flesh and blood had locked him in a cell to rot with three impeccables. Three women. And when Jafar had begged? Put aside his pride, got down on one knee and begged? His son- Jay- High King Jay the Avenger had laughed at him, called him weak and useless and petty. Said that anyone who was on the Isle in the first place did not deserve a second chance, because they were not strong enough. But his underlying meaning rang in Jafar's ears. Not cunning enough.
But Jafar was always cunning. And so he made a plan with Maleficent. When she died, he attempted to escape, to slip away unnoticed. He was caught, and the four sovereigns, his Kings and Queens, laughed. They shook and cried with laughter. And ignored him. Him. The once-Most Trusted Advisor to the Sultan of Agrabah. Then they carted off Grimhilde and broadcasted her murder on live television, and he knew, he knew he was next. Because, no matter what he said, Cruella's son was always scared of her, even all these years later.
Officially, he wasn't the last one to die. But he wasn't the last one to leave either. One day, a servant (slave) of that infernal son of his came to fetch him, and cuffed him, and dragged him to the throne room, where King Jay lounged on his throne, with his feet on Cruella's son's lap, and his head in Grimhilde's daughter's lap, the little bitch stroking his hair, and Maleficent's spawn stretched out on her throne. And they cast him out to die in the deserts in Agrabah.
But before he died, Jafar went mad. His genie powers came in to play, but there was no lamp, so he was left to lament his old life and regret his bad choices with his son(s). And when he stumbled across a perfectly clean and loaded pistol in the middle-of-nowhere, he didn't think it strange, that it was maybe a plot. He just died. Because he was mad.
(Because Jafar was never cunning, only insane, and Jay proved it.)