Humberto Lopez' parents were paleontologists who dug up a crystallized bone while he was with them in the desert. The medallion had weird energy that was connected with dinosaurs. Under the codename Reptil, Humberto used it to enable him to obtain the abilities or traits of any dinosaur just by thinking of it (although he was limited to one ability or trait at a time), and even had an empathic sense that could detect dinosaurs and other reptiles. His parents later disappeared while on a dig. Humberto registered with the 50-State Initiative while living with his grandfather.
When S.H.I.E.L.D. scientist Valerie Cooper was putting together a squad to go after Stegron to prevent his plot to reanimate dinosaur fossils. Tigra was placed in charge of the squad and was told to recruit Humberto to help them. Tigra was worried about his abilities, since Humberto hadn't gone through any training yet. Upon arrival at Camp Hammond, Reptil went through some basic training for a couple of days. While going through training with different members of the Initiative, Reptil learned there were both good and bad aspects of the Initiative. Tigra told Reptil that being a hero is a responsibility. Humberto wanted to become a hero to use his powers for good.
With the help of Baron Von Blitzschlag attaching some type of neuron device to him to increase Humburto's empathic sense, the team located Stegron. When discovering that Stegron and his dinosaur herd were going to attack a S.H.I.E.L.D. base in South Dakota, Tigra's group intercepted them. However, Stegron took control of Komodo's mind and coerced her to attack her teammates. Reptil was hot-headed and impulsive during the fight and attacked Stegron, but was soon beaten and Stegron and his dinosaur herd escaped. Reptil had suffered a mild concussion and Dr. Cooper told him that his rash behavior had allowed Stegron to escape and endangered the lives of his teammates. Tigra spoke to Dr. Cooper in private and asked her to give Humberto one more chance to go out in the field. Valerie told Tigra that if Reptil messed up this time, then his career with the Initiative would be over. Tigra spoke to Humberto a few days later and reminded him to stay balanced and not to overcommit. She told him that everyone had problems and that he was lucky enough to be in a position to learn from other people's mistakes as well as his own.
When they attacked a S.H.I.E.L.D. base in Wyoming, Stegron's dinosaurs were soon taken down by a combination of good teamwork on Tigra's team's part, and Reptil's abilities in particular. It turned out that Stegron was attacking various S.H.I.E.L.D. bases to locate Moon Boy (who had been captured from the Savage Land). Stegron was only targeting Moon Boy so that he could gain control of Moon Boy's companion Devil Dinosaur. Reptil told Tigra that Moon Boy was innocent and didn't deserve this treatment. Reptil managed to fly away from the scene with Moon Boy and take him back to his home in Nevada. Tigra told the S.H.I.E.L.D. scientists and agents that Moon Boy had been eaten by one of the dinosaurs and Reptil was sent home because he was not ready to work in the field.
Tigra met Humberto back in Nevada and they were soon greeted by Ka-Zar and his pet smilodon Zabu. Ka-Zar thanked Tigra and Reptil for bringing Moon Boy back to him safely and invited Reptil to take Moon Boy back to the Savage Land. After Moon Boy was reunited with Devil Dinosaur, Ka-Zar promised Reptil that he would help him find his parents.
Soon after Reptil was recruited to be part of the Avengers Academy. He was elected leader soon after their identities were exposed and had a minor relationship with Finesse. When Mentallo was attacking the city Reptil had to go fully dinosaur mentally, but had a conference with the instructors. And soon after Jessica Jones to talk about his emotional problems evolving his parents and Norman Osborn.
Reptil is 1 of 16 people confirmed to take place in Avengers Arena. A game of kill or be killed.
Reptil can take on the traits of any dinosaur, but is limited to one trait at a time. So far he has shown the ability to take on the wings of a pterodactyl, the tail of a stegosaurus and ankylosaur, the head of a parasaur, and the head of a tyrannosaurus. He's also taken on the legs of an unidentifiable dinosaur and the enhanced sense of smell of a dinosaur.
Reptil can sense the presence of dinosaurs and track them.