Riddlebat

Riddlebat is the slash ship between Edward Nygma and Bruce Wayne from the DC Comics fandom.

Canon
Edward and Bruce are enemies. Their rivalry starts when Edward begins his crime wave in Gotham City. So Bruce has to solve some of his puzzles and ends up getting Edward sent to prison. After his release, Edward starts his quest to get all of Bruce's attention. So he plans even more complex puzzles and riddles for Bruce to solve.

Batman: Hush
In Hush, Edward allies himself with the criminal known as Hush to help him get revenge on Bruce. As Bruces chases Edward down, he starts thinking about him. Bruce thinks about the life Edward has had as The Riddler. And then thinks about the way in which everything in Edward's life has become routine. As he drags Edwad along, he keeps thinking about how he could have been ignored by the rest of the villains.

Some time later, Bruce goes to see Edward at the Arkham Asylum he was staying at. There, he starts interrogating him about working with the other villains he had inside information about. Bruce also lets him know that he knows that Edward was diagnosed with terminal cancer. Then he questions how Edward got suddenly cured. And Edward confesses he knows Bruce's real identity as Bruce Wayne, beyond his Batman persona. Then, Bruce counters by asking him "what time is it when an elephant sits on a fence?" And when Edward scoffs at this, saying that's a riddle that everyone knows the answer to, Bruce leans in, and tells him that he knows Edward, even better than he himself knows him, which is exactly why he’ll never tell anyone that Bruce Wayne is Batman. Because a riddle that everyone knows the answer to isn’t a riddle at all. After hitting Edward, when he mentioned how Bruce's greatest weakness was Robin's death, Bruce leaves him behind.

Detective Comics
After a year-long coma, Edward loses all of his memories, but still has his intelligence and deduction skills intact, which is why he becomes a detective. He even begins working with Bruce to resolve some murder cases in Gotham, but not fully remembering he is Batman. The two of them start having a frenemies-type-relationship, where Edward frequently teases Bruce.

Later, when the two of them meet aboard a ship, Edward seems to regain some of his memories, as he instantly recognizes Bruce without his costume, although Bruce doesn't realize this yet. When one of Bruce's friends gets killed on the ship, he decides to track down the suspected killer, and when he arrives there, he finds Edward beaten down on the floor, who came to do exactly what Bruce was planning on doing. As he struggles with the killer who was about to throw him out the window, Edward saves his life by shooting a flaming arrow at the killer.

Behind the Scenes
"It’s a love story. That’s what this is. He [The Riddler] loves him [The Batman]."

- Matt Reeves (Director of The Batman 2022)

Fanon
Although there were Riddlebat fans before the release of The Batman (2022), a large portion of them came from that movie. Showing that The Batman and The Riddler aren't all that different showed many fans that they could bond over that.

Bruce and Edward are typically written as enemies to lovers (as they would be if the ship was entirely canon), sometimes writers have AU's where they were never enemies and or where Edward wasn't a murderer to make the relationship a bit sweeter.

Fanfictions typically tend to keep the personalities of Bruce and Edward, and both of their alter egos (The Batman and The Riddler), making it so Edward is in love since the beginning and Bruce is the last one to realize his feelings.

Also, fans tend to make Edward and/or Bruce transgender and/or autistic. Edward being the one that is mostly depicted at transgender, and both of them (pretty equally) being depicted as autistic.

Fandom
FAN FICTION