“How ‘bout we try real game for once and play some ball, champ?” is Edward Nashton’s childhood, and he hates it. His father tries to make him into the son he wishes he had, neglecting him and destroying his puzzles when he doesn't succeed. Since Edward isn't left with bruises, nobody cares.
It doesn’t matter. He survives, he gets good grades. He saves up over years of summer jobs at the yearly fair, he learns to break through security systems for the thrill as well as the necessity, and he leaves on his 18th birthday.
His first act is to change his name to Edward Nygma. It fits a genius of his caliber better. (And he doesn’t care for how his hands don’t keep steady when someone asks for a Mr. Nashton.)
He’s accepted into Gotham University, and his room is on campus, but anyone would say he lived in the labs. He meets and falls for his lab partner, Julie, and he spends his time with her inventing a fantastic creation, the bio-harddrive.
It’s amazing, a patch placed on the forehead that improves memory and logic to abilities beyond even his own. It’ll do more than merely gain them fame and fortune—it will help everyone who has problems with remembering phone numbers, can’t solve nasty math equations, and worse.
It catches attention. Edward doesn’t care for the main source of it—Chuck Gorman, businessman, head of Gorman Enterprises. He wants to work with them. “We’ll make a whole lotta money together.”
He reminds Edward of his father even before he calls him champ. He refuses, shoves Gorman away, and Julie asks him why.
He doesn’t want to upset her. He explains about his father and how Neanderthals like Gorman would only hold him back; she listens, she understands, and he’s grateful.
They demonstrate the bio-harddrive, later. The University President let Edward use it on himself. It works well enough for the memorization of an entire textbook on the laws of physics—and then it malfunctions. The President is left braindead.
Edward is kicked from the university. He has nothing left, nothing going for him but the thought of revenge; Gorman ruined him, sabotaging his work to get his hands on Edward's technology, he’ll ruin Gorman in return.
He takes over the man’s house, riddles it with traps, and he nearly manages to crush him before a new player intervines. The Batman. He solves Edward’s riddles, thwarts every remaining trap, and was the closest to succeed in catching him than anyone had come before.
Edward is inspired that night. He needs toys like the Bat’s, maybe some fashion sense, too. Edward Nygma is discarded, The Riddler is fully formed. There’s no going back.
He bides his time, building connections, finding himself a pack of loyal henchmen, and his debut is two years later. He has his fun, at first, forcing the Batman and Detective Yin an a merry riddle-solving chase across all of Gotham—but in the end, he loses.
He challenges Joker and Penguin, a wager, whoever catches and unmasks the Bat would win; he gets the closest, but the pair team up and nearly kill him, and the Batman takes him down after once again.
Between crimes, along with most of Gotham's supervillains, the Riddler is imprisoned in the unpleasant institution for the criminally insane, Arkham Asylum.
All this time, he allows Gorman to “fix” his bio-harddrive and taste success. That revenge is best served cold may be a cliché, but it’s hardly a lie.
Riddler’s goal in destroying the ship filled with the bio-harddrives is met, but the Batman saves Gorman once again. Gorman flees and uses the bombs Riddler himself was going to use just to get rid of Riddler. The Batman and the villain end trapped beneath debris at the bottom of Gotham Bay in a crate.
Riddler tells the Batman his story. They’re going to die—it doesn’t matter. He ruined Gorman, that was as good a note to go out on as any. (All those years ago, he hadn’t expected to leave Gorman’s house alive himself; he’s too bitter to count himself lucky for the extension, but he can acknowledge that it exists.)
The Batman listens.
And he proposes something that shakes the Riddler’s very foundations.
Gorman might not have been the one to sabotage the project after all.
He works with the Bat to bring the crate back to the surface. His waiting hired hands rescue him, distracting the Batman enough for Riddler to nearly take him out once and for all. Robin manages to stop him, but Riddler manages to escape and tells the thugs where they’re going next: the labs of Gotham University.
For the first time since he was kicked out, he sees Julie face-to-face. She knew he’d come back someday, and it takes almost nothing to make her smugly admit what she’d done, that she’d sabotaged the bio-harddrive. After he told her about his father and his past, she "realized" Edward was a psychopath that would ruin any chance of success. So she got rid of him.
Betrayed and enraged, he tries to kill her. The Batman manages to find him first and stops him, leaving an unconscious Riddler and a bound Julie for the police.