Jason Todd was the surrogate son and protegee of Batman known under the mantle Robin (after Dick Grayson left the mantle to him by becoming Nightwing), before he was killed by the Joker and Harley Quinn.
Jason Todd was a former street kid taken in by Bruce Wayne in between 2010 - 2011 after his first surrogate son Dick Grayson moved on to become "Nightwing", with Jason served as the second "Robin" alongside Batman during his time as a vigilante in Gotham City, New Jersey.
However, in late 2012 - early 2013 Robin was eventually trapped, tortured and murdered by the Joker and Harley Quinn. The psychopathic duo left his damaged Robinsuit graffitied with the sentence "Hahaha joke's on you, Batman" for the devastated Dark Knight to find.
A devastated Batman kept Robin's old damaged suit in a glass case in the Batcave to serve as a reminder and fuel for his vigilante activities. Jason's death was also one of the major reasons for Bruce becoming more enraged, hardened and vengeful, and therefore inducing him to take a more hardcore approach in stopping crime. Right before leaving for Lex Luthor's fundraiser (where he planned to acquire data on Kryptonite), Bruce pauses to look at Robin's suit, reminding himself of why he continues to do what he does, and how taking down Superman will avoid more potential losses.
- Peak human condition: Jason Todd, due to his initial experience on the streets of Gotham City, the training he did under Batman before becoming Robin, and the later frequent intense Batcave workouts and numerous vigilante escapades in the city, heightened his abilities to the highest levels of peak human potential, allowing him to serve alongside the highly skilled Batman.
- Skilled combatant: Robin was well trained in armed and hand-to-hand combat under Batman's guidance, which made him extremely skilled in martial arts, enough to serve alongside Batman as his sidekick vigilante, despite only being a teenager. He may have also been a skilled fighter even before becoming Robin, as he was a street kid before being taken in by Bruce. Notably, however, Robin was ultimately subdued, defeated, and killed by the joint effort of Joker and Harley Quinn.
- Human vulnerabilities: Robin's greatest weakness is that he is a human with no enhanced strength, speed, durability, or metahuman powers, therefore making him quite vulnerable to the physical attacks of stronger and more powerful opponents. Robin, however, usually compensates for this quite well with his highly durable fire- and bulletproof Robinsuit, exceptional combat skills, and highly sophisticated technological gadgets. However, despite all of his combat skills and weapons, Robin was ultimately defeated and beaten to death by Joker and Harley Quinn.
- Robinsuit: Robin's highly durable protective suit and combat armor (inspired by the Batsuit and originally worn by Dick Grayson), used to compensate for his lack of invulnerability. It is invulnerable to knives, small-caliber bullets, and is also fireproof. After Jason's death though, the Robin suit would be defaced by the Joker and Harley Quinn, who spray-painted a mocking message to Batman on it.
- Combat staff: Robin wielded a long staff in combat.
- It was confirmed the Joker killed Robin in an interview with Zack Snyder. However, it was revealed in Suicide Squad that Harley was also involved in Robin's murder.
- In the DC Comics universe, Jason Todd takes up the Joker's former mantle "Red Hood", after his resurrection (via the Lazarus Pit), and then goes on a rampage, seeking vengeance on Joker, as well as Batman, albeit to a lesser extent against the latter.