Jaguar is an enemy of Daredevil and Captain America (the latter because he worked with HYDRA. He was one of the victims of the Scourge of the Underworld.
El Jaguar's origin, or even his native country, are unknown - although his name and alias suggests some place in Latin America. As of today, the origin of his powers is still unclear. He was probably a mutant, or an altered human, and terrorist organization HYDRA might be responsible of his alterations.
El Jaguar was the leader of an elite commando unit on HYDRA, alternatively known as Bravos Commandos and Commando Division. One of those commandos was famous assassin Horst Eisele. Jaguar and his commandos were loyal to the Supreme Hydra, who was at that time Silvermane.
HYDRA's enemy organization S.H.I.E.L.D. publicly contacted with district attorney Foggy Nelson to join its board of directors. HYDRA marked Nelson as a target, and ordered Jaguar to murder him.
Jaguar and his commandos attacked a New Year's Eve party Nelson was invited to. Nelson's partner Matthew Murdock also was there, along with his girlfriend Natasha Romanoff - who were also known as costumed superheroes Daredevil (Matt Murdock) and the Black Widow (Natasha Romanoff). Both of them changed to their secret identities and fought the terrorists.
El Jaguar was more than a match for any of them: He defeated the Black Widow and fought Daredevil to a stalemate. However, the tables turned due to the opportune arrival of SHIELD agents led by Nick Fury. El Jaguar ordered a complete retreat, and went to explain his failure to his leader.
Jaguar then met with HYDRA agent Blackwing in a warehouse near the Shea Stadium. Both were unaware of Daredevil and the Black Widow tracking Blackwing. The Black Widow, still humiliated for her previous defeat, fought El Jaguar while Daredevil battled Blackwing. El Jaguar was nevertheless too strong for the Widow to defeat. In a last-ditch effort, the Widow prepared her widow's bite in killing position, but she only managed to knock El Jaguar down!
However, Blackwing defeated Daredevil and, later, the Widow. Another HYDRA agent, Man-Killer, took unconscious Jaguar to the Supreme Hydra in a subterranean base under Shea Stadium. El Jaguar would not recover his consciousness for a while.
When he awoke, the heroes had recovered and were launching a counter-attack. SHIELD had also found them and launched their own commandos. Jaguar tried to fight SHIELD agent Dum Dum Dugan, but was defeated by being slammed to a wall. Although the Supreme Hydra and Blackwing managed to escape, Jaguar and the other Hydra agents were arrested by SHIELD.
Years later, Jaguar was at large. It is unclear if he kept his association with HYDRA. He was contacted by Gary Gilbert, a former costumed criminal turned into business agent for criminals. Gilbert was worried about the Scourge of the Underworld, a masked figure who was killing costumed criminals such as Gilbert and El Jaguar. Gilbert organized a meeting in the The Bar with No Name, Medina County, Ohio, to discuss potential counter-attacks. As the Scourge was known to use weapons instead of powers, weapons were to be left at the door. However, the Scourge infiltrated in the meeting disguised as the bartender and shot down all the seventeen criminals (including El Jaguar) wielding a cut-down .50 sub-machine gun in each hand.