James Rogers is the son of Captain America and Black Widow. After James was born, he and the rest of his adopted siblings were secretly hidden within the arctic base to be safely raised byTony Stark. James along with his other siblings only knew of theAvengers through Tony's tales of their former glory days. Bred into a life of constant training, James eventually became weary of constant routine and started falling behind in his training as he no longer sees a point in them. After the arrival of Vision, James and his siblings got too curious for their own good and followed Tony to reveal a secret entrance to a repair bay, under their parent's grave. While with Torunn, he found the Iron Avengers(ironman-based bots tuned after each fallen Avenger). Unable to resist the idea that Iron Captain America could possibly have answers to his father, he accidentally activated the robots and their automatic programming sent them to intercept Ultron. Not realizing the danger he caused, the Iron Avengers attacked and was assimilated by Ultron.
Ultron eventually made his way to the Arctic. Iron Man/Tony Stark appeared to stall precious time as James and the others ran for their lives (escaping with Vision's head). The shuttle was predestined for a safety zone, but the children figured a means redirect the shuttle to Ultron's citadel for a counteroffensive. Their first attack was a failure and nearly cost their lives if it wasn't for the unexpected aid of Francis Barton (Clint Barton's son) and hisScavengers.
As James and his siblings followed Francis, they learned he's the surviving son of the original Hawkeye. Francis was infuriated to know that he wasn't the lastAvenger and angrily wondered the whereabouts of the other Avengers during his time of desperate survival. James and the others reasoned they didn't know of his existence. As they reached to the remains of NYC's Grand Central Station, the young Avengers seeked Francis' help to rescue Tony. Francis believed Tony is good for dead, but an elder Betty Ross suggests that Tony is very much alive. The news renewed their hopes and James unsuccessfully attempted to recruit Francis to rescue Tony; Francis gave the young Avengers instructions how to reach Ultron's lair.
Successfully infiltrating Ultron's lair, they found Ultron's private collection of the fallen heroes that challenged him, including a trophy room of the fallen Avengers. James and the others were sadden after seeing the remains of the Iron Man armor, suggesting Tony had fallen. James was then distracted after seeing the remains of Captain America's costume behind the case. Their time to mourn was short as the room began to transform. Ultron revealed himself along with a still-alive Tony Stark.
Ultron warned the young Avengers of their impending doom. Ultron intended to destroy James first as his father was a great threat to him (in terms of his ability to lead and inspire hope in people, believing James is the same kind of threat). Francis and his Savengers showed up to distract Ultron along with the other young Avengers long enough to rescue Tony. Ultron commanded his robots to search and destroy them, but James and the others managed to escape to safety.
In a abandoned theater, Tony explained to James and the others of Ultron's origins and the fall of the Avengers. Betty Ross was also present and mentioned of the still-alive Hulk, hiding in safety. James and the rest of the group decided to venture into the desert in a abandoned robot transport in hopes to enlist Banner/Hulk; once there, Banner refused to help them. James motivated the rest of his team to push forward for the sake of their fallen parents. They decided to activate a homing beacon within the stolen robot they used for transportation to lure Ultron, forcing Banner/Hulk to face Ultron.
Ultron took the bait and attacked with his Iron Avengers, each of the children facing the iron-imitations of their parents. James fought against Iron Captain America and Iron Black Widow. During their fight, James' shield generator was damaged, but managed to take back the original Star Shield from Iron Captain America. While still fighting against his iron-imitated parents, James had Pym lure Hulk out from within Banner. Shortly after, Hulk returned and defeated Iron Ant Man and Iron Black Widow to face Ultron. James and the rest of the youngAvengers defeated their iron-imitated parents.
Ultron temporarily knocked out Hulk in the battle and re-focused his attention to kill James. Ultron blast a powerful beam from his chest in attempts to vaporize James. James used his father's Star Shield to hold on as long as possible until Hulk returned. While Ultron was distracted by James, Hulk grabbed Ultron and finally broke the robot in half. Hulk then turn his attention against the young Avengers, but Betty calmed the Hulk. After Hulk left, they realized that Ultron was still active, regenerating himself. Torunn made the ultimate sacrifice by throwing Ultron's split body into the depths of space. James and the others was worried over the fate of Torunn, to their pleasant surprise, Torunn returned in new armor from Asgard (courtesy of Thor). James and the rest of the Avengers now set their sights in destroying what's left of Ultron's forces, ensuring the freedom of Earth.
Powers and Abilities
James' full capabilities were never clearly defined; he's been trained in combat similar to Captain America. As the product of two super soldiers, it's unclear was James born normal or also inherited his parents super soldier enhancements as well.
James' strength was unclear as his abilities were never clearly defined. It's only theorized he has the human peak human strength in the qualities in both his parents.