Jason Todd

"Blindly, stupidly, disregarding the entire graveyards he's filled. The thousands that have suffered. The friends he's crippled. You know, I thought...I thought I'd be the last person you'd ever let him hurt. If that had been you that he'd beat to a bloody pulp... If he had taken you from this world...I would have done nothing but searched the planet for this evil, death worshiping garbage, and sent him off to hell!"

- Jason Todd (confronting Batman over letting Joker survive)

Jason Todd was once one of the main protagonists in the Batman comic books, but he was killed by the Joker and was later revived by the effects of Superboy-Prime. Because of this he became enraged and took the identity of a villain called the Red Hood II.

Background And Taking Red Hood Mantle
Jason grew up on the streets for a while before he was found by Batman. In the movie he was seen trying to steal the tires off of the BatMoble. After of which he was taken in by the man. He later on became the second Robin. However, Todd was more violent and aggressive. After being suspended from being Robin, Jason went on a personal quest to find hs biological mother. When he found her, he was beaten and demolished by the Joker. Before dying in Batman's arms, Jason's mother tells him that Jason tried to shield her from the explosion and died a hero.

His death didn't last forever, because of the effects of Superboy Prime who was attempting to escape from a supposed "paradise". This caused a ripple in reality, which caused Jason to awake inside his coffin. Jason was revived, but his brain was damaged and had no memory of his true identity. He wandered for years until he encountered both Ra's and Talia al Ghul. Both of them took him in. Talia submerged Jason in a Lazarus Pit and re-awakened his all of his memories completely intact. When he found out that the Joker was still alive, Jason was enraged and decided to take on the identity of the second Red Hood, and became one of the scourges of Gotham's underworld.

One Year Later
In the One Year Later arc, Jason becomes the murderous version of Nightwing and patrols the streets of New York to kill criminals but was confronted by the original Nightwing Dick Grayson. Grayson saves Todd from a group of mobsters. After the events of the One Year Later period, he redons the Red Hood persona.

New 52
During the New 52 relaunch, Jason as Red Hood was placed into his own series Red Hood and the Outlaws where he has formed his own three-man team consisting of himself, Starfire and Green Arrow's former sidekick Arsenal. Also his violent nature has been toned down for the new series as he is not as eager to kill as he had before and would only use his guns to wound instead of kill. He is still viewed as a criminal in the eyes of Batman and his other allies.

Issue 0 of the series does a retelling of Jason's origin which is about the same as before except that since Superboy Prime does not exist in the new continuity, the Lazarus Pit was used to bring Jason back to life.

After Starfire left the team (as she was given her own solo series) the series was cancelled and replaced with the new series Red Hood/Arsenal which now focuses on just the two-man team between Red Hood and Arsenal.

Teen Titans
Though Jason Todd didn't appear in the TV Show; Teen Titans, he does make a brief cameo, and there has been rumors that one of the villains known as Red X is really Jason Todd behind the mask.

Batman: Under the Red Hood
See: Jason Todd (Under the Red Hood)

Ra's al Ghul, out of guilt for his unintended role in Jason Todd's death, secretly replaced his corpse with a realistic dummy, and proceeded to use the Lazarus Pit to resurrect him to repair the damage in hope by the time Jason fully recovered, he will reunited him with Batman. Unfortunately, this had disastrous side effects: While Jason Todd's body was resurrected, his mind was left damaged. He then proceeded to escape custody of the League of Shadows, narrowly survived falling into the nearby river from a high drop, and somehow managed to find his way back to Gotham five years later. Upon hearing that Batman only sent Joker to custody, Jason Todd was enraged, and proceeded to adopt the former identity of the Joker, the Red Hood, and proceeded to take control of the various drug dealers under the employ of Black Mask, allowing them to continue dealing on the streets under the condition that they pay 40% of the shares to him, and they stay away from children when dealing drugs, threatening to kill them should they disobey (also producing a duffel bag containing the decapitated heads of their various lieutenants that he allegedly did in under two hours to make clear that his threat was genuine) as means to plan his vengeance on Batman.

Young Justice
Although you do not see Jason appear in Young Justice he is shown breifly in a few of the episodes. He is seen with the other members that have passed away, one of the holograms that is left for them to respect those that have passed. There is a speculation that at some point he will in the show as "The Red Hood". However, as of Endgame, most of that has been canceled in the minds of many fans for the reason that Young Justice is not supposed to be returning with a third season.

Batman: Arkham Knight
See: Arkham Knight

After Batman vanquishes Jason's Arkham Knight persona, Jason lays his desire for vengeance against Batman to rest and becomes the Red Hood. After helping Batman take down Scarecrow, he turns his attention to the syndicate owned by Black Mask. Jason tracks down some of Roman Sidoni's men and kills all but one of them. He interrogates the goon into revealing the weapons were stored at the docks, who he then executes. After killing all but one of the thugs in the docks, Jason visits Black Mask's hideout where he murders all of the remaining henchmen. As Sidonis desperately begs for his life, Jason kicks him out of a window, which kills him and ends his hold on Gotham City's underground.

Injustice 2
Jason as Red Hood will make an appearance as DLC in Injustice 2.

Skills

 * Expert Martial Artist: Jason Todd, having been trained by Bruce Wayne - who has mastered every single form of hand-to-hand combat and martial arts known to man - himself, was an expert martial artist. He was capable of defeating multiple opponents simultaneously by manipulating or breaking limbs and spines, and even using one person's body as a shield or offensive weapon against another's. He was even capable of holding his own for a very long time against Batman, but was ultimately defeated. His fighting style, unlike Batman who emphasized brutality and his environment as a weapon but never to kill, emphasized incredible brutality, as well as using knives and guns, with the expressed intention of killing.
 * Marksmanship: Jason was also a highly skilled marksman with machine-guns and pistols, primarily any form of small guns that could be utilized in intense or time-dependent combat situations. He was capable of shooting a man at a long distance, whilst being physically attacked by several other opponents.
 * Athlete: Jason was an incredible athlete, and capable of using his environment and even opponents to execute extraordinary gymnastic or athletic movements in order to escape, attack, defend or approach situations or people. Jason was capable of back-flipping or cartwheeling directly after being struck in the face by an extremely strong opponent, like Batman.
 * Peak of Physical Condition: Jason's physical prowess was impeccable, as he could run, fight or take enormous amounts of physical strain for an enormous amount of time.
 * Master of Criminology and Strategy: Jason, having been personally tutored by Bruce Wayne, possessed an intricate knowledge of criminal psychology, strategy and techniques, and received a classical education from the same man, making him highly intelligent but also dangerous to a fault because of his cunning.
 * Stamina: Jason was extremely resilient, and could withstand enormous amounts of physical and mental torture from the Joker for days on end.