The Birth: The New Mexican tribesmen had for years been performing genetic experiments to alter the human form. Their experimentation bore fruit when a member of their tribe, Thomas Fireheart was genetically changed into a mutant, bonding with the Puma. Fireheart, in his altered form, simply took the name; Puma. His first appearance was in Amazing Spider-Man #256.

The Alter Ego: Thomas Fireheart, a native American is the traditional protector of his New Mexican tribe, although he himself often questions the traditional rituals that his uncle, the tribe's Shaman, espouses. He ventured out into the world to seek his fortune. With his genius level IQ, he post graduated with a Masters degree in Business Administration and eventually became the C.E.O of Fireheart Enterprises.
He has travelled the globe, both as his company head and as Puma and has visited places like Tokyo, New Mexico, and France. With his criminal mind and his Mexican tribe upbringing, he had a warped sense of ideals and is bound by a sense of honor that only he understands.

The Legend: Puma first crossed the path of Spider-Man when he was hired by the Rose to "remove" the Web-Slinger. In his altered form, he is even more tougher than Spidey, so it was a good thing that Rose changed his mind. Later on, Puma sought Spidey's help when he discovered that he was destined to fight the Beyonder; Spider- Man refused, making Puma doubt himself and, eventually, fail in his quest against the Beyonder. Puma publicly confronted Spider-Man over a story in the Daily Bugle that made it seem as if Spidey was a thief; when the story turned out to be false, Puma felt as if he had lost face and was now honor-bound to clear Spidey's name. To this end (and much to Spidey's annoyance), he purchased the Daily Bugle and began a campaign of positive promotion which was largely responsible for the public perception of Spidey as a hero.
Puma's animal side became dominant after contact with the Black Crow. He was seriously wounded in a fire fight with the New York City Police, but nursed by to health by Nocturne, who was eventually able to restore his human psyche.
Puma has above-human senses; he can, for instance, see auras. Since he transforms into the Puma through concentration, he may be considered to have some mental abilities beyond the norm. Puma's powers are from years of genetic engineering, although given his uncle's status some mysticism may be involved. Puma has also received training in the martial arts in Japan and has above normal traking ability. When he faced the Beyonder he briefly had cosmic powers beyond understanding. How he was able to tap into the universal energies needed to confront the Beyonder, and if he would be able to do so again, is unclear; his uncle called Thomas the chosen champion of Death, so it may have been through Death's intervention that Fireheart was able to do harness the needed cosmic energies the first time.
Inspite of being known in international circles as one of the best assasins, he has no criminal record whatsoever.

Amazing Spider-Man #256