My Hero Academia's has finally revealed the true origin of Dabi, the pyrokinetic psycho who has been one of the series' most fearsome villains. We now know (for sure) that Dabi comes from one of the most prominent pro hero families around, in My Hero Academia, and if that wasn't enough, Dabi took that dark secret and used it to pull off a larger scheme to destabilize the entire pro hero world. With this big reveal moment, My Hero Academia has taken Dabi from being a secondary henchman in the League of Villains to a chaos-sewing sadist on the level of DC's Joker. In fact, My Hero Academia anoints Dabi with Joker-status by having the villain perform a full-on ode to Joker movie.
As you can see in the side-by-side comparison above, My Hero Academia creator Kohei Horikoshi seems to have definitely thrown in a Joker movie reference in this scene of Dabi gleefully dancing to the tune of chaos. Since Joker movie's release in 2019 (and subsequent Oscar wins this year), the film has inspired an entire wave of memes and quotes that are now circulating the Internet, inspiring spoofs and/or homages. Horikoshi is notorious for having My Hero Academia pay homage to the sci-fi/superhero works that have (and continue to) inspire it. It only fits that Joker would get a shoutout, as well, given the cultural milestone the film has become.
WARNING: My Hero Academia chapter 290 SPOILERS Follow!
The big reveal in My Hero Academia 290 is that Dabi is indeed Toya Todoroki, the son of Enji Todoroki (aka no. 1 hero Endeavor), and the older brother of Shoto Todoroki. Toya was Endeavor's first attempt to create an even more powerful successor to his own flame powers; Toya had a powerful flame, but his mother Rei's ice power made it unstable. We were told that Toya died in some kind of tragic accident, but clearly, that's not the case.
Dabi claims that he was a "failed experiment" that Enji "tossed aside." That leaves room for more backstory to be filled in later, regarding what happened to Toya to make him break from his family, and become this Joker-type antagonist in My Hero Academia's story.