During the Kree-Skrull War, the Super-Skrull kidnapped Captain Mar-Vell, Quicksilver and the Scarlet Witch and presented them to the Skrull Emperor. While the heroes later escaped, the Emperor's daughter, Princess Anelle, conceived a child with Mar-Vell. At birth, the child was immediately exiled and grew up on Earth as Theodore "Teddy" Altman. The Empress ordered her child's nurse to protect Teddy. She posed as a human working in real estate and raised him as a single mother.
On Earth, Teddy used his powers mainly in an effort to fit in with his high school classmates, particularly the class president and basketball team captain, Greg Norris. Fitting in for Teddy included using his shapeshifting to provide access to New York City high life by impersonating various superheroes and celebrities. Finally, when Greg coerced him into breaking into the ruins of Avengers Mansion, Teddy decided that some things were more important than fitting in, and rather than let Greg loot the mansion, he ended the friendship.
Teddy was one of the people listed in a fail-safe program compiled by the Vision to be used to form a new team of superheroes in the event of the destruction or disbanding of the Avengers. Iron Lad, a younger version of Kang the Conqueror, found Teddy using the Vision’s failsafe program and requested his help in preventing his future self from returning him to the future. Teddy joined the Young Avengers and adopted the super-hero identity of the Hulkling. He began dating his teammate Wiccan.
Teddy's life changed again when the shape-shifting extraterrestrial known as the Super-Skrull showed up, claiming that Teddy was a Skrull. The Super-Skrull was surprised to learn that Teddy had super strength and wondered "perhaps the rumors about his father are true."
The Super Skrull followed the Young Avengers to the home of Wiccan, where Teddy's mother was waiting for him. The Super-Skrull released a device designed to turn Teddy into his true form, trying to prove to him his Skrull heritage. But the device didn't change Teddy's physical appearance. Instead Ms. Altman, who was also caught in the device's beam, turned into a Skrull. When the Super Skrull accused her of being a traitor to her race, she responded by saying that the Empress ordered her to protect Teddy. Before she could say much else, the Super-Skrull killed her and kidnapped Teddy.
The Super-Skrull broadcasted to all Skrull worlds that he had located Dorrek VIII, though Teddy insisted that he's not a Skrull. Kl'rt insists that he and revealed the truth about his past. He insists that he must return to his people so that they may reunite the Skrull Empire. Kree soldiers then arrived to help Teddy, stating that the Kree looked after their own. A battle then erupted between the Kree and the Skrull, both claiming Teddy as their own. The only solution that Teddy saw to end the war was surrender. It was settled that Teddy would spend half an Earth-year with the Kree and the other half with the Skrull, at which time he would declare his ultimate allegiance, while also being able to make scheduled visits to Earth. However "Teddy" was the Super-Skrull disguised as him, therefore the real Teddy stayed on Earth.
Along with the rest of his team, Hulkling sided with Secret Avengers against the Superhuman Registration Act, which led to the Civil War. He played a pivotal role in Captain America's plan for the final confrontation with Iron Man's forces, impersonating Yellowjacket in order to free the imprisoned heroes of Prison 42.
When the Skrulls invaded Earth, Hulkling joined the Young Avengers on the frontlines and tried to talk to the Skrulls since he was Skrull royalty. The Skrulls ignored him and swiftly took him out. He was a target of the Skrull Queen because of his royalty. Before he could be executed, Xavin of the Runaways (a Skrull himself) intervened and saved Hulkling.
Metamorph: Hulkling is a shapeshifter of remarkable ability. While he most commonly shifts into a teenaged version of the Hulk, he has also been known to impersonate well known superheroes such as the Human Torch, Mister Fantastic, and Tony Stark. In the heat of battle — or of the moment — he has evidenced a less refined style of shapeshifting: growing claws, extending his reach and growing wings in a protoplasmic manner.
Superhuman Strength: Hulkling is much stronger than an average human, and stronger than even most Krees are because of his partial Skrull background. He is rumored to be above Strength Class 100.