Captain America is considered by many to be the moral center of the Marvel Universe; a symbol of goodness that is always driven to do the right thing no matter the cost. Being such a boy scout, one expects him to be a consistent source of commendable deeds, so it might come as a bit of a surprise to find out that he once kidnapped a child and raised it as his own. No, that is not a joke, Cap seriously once stole a child.
It may make one feel slightly better to know that the child he kidnapped was that of a villain, but that doesn't change the bizarreness that is the situation of Captain America's adopted son. Back in 2012, the creative team of Rick Remender and John Romita Jr. sent Steve Rogers off on a wild and tragic journey known as Castaway in Dimension Z, in which this son is found and raised.
The TLDR doesn't do it justice, but the basics are this; Cap gets sent to another dimension where he finds himself captured next to Arnim Zola's test-tube baby. Cap kidnaps the baby and raises it as his own in this hellish dimension while they live on the run. The child gets taken back by Zola's other child, a daughter named Jet. Zola brainwashes the child to hate Cap, leading to a father/son showdown. The child nearly kills Cap, only to be killed himself. The child, revived with life, comes to the normal universe as a fully grown adult and becomes a superhero of his own. While that's the general gist of it all, that seriously doesn't say enough about how bonkers this entire tale really is. It truly pays off to get the full scoop, starting from the beginning, with good ole Captain America being snatched by an... interdimensional locomotive.
Finding himself captured by, yes, a train, Rogers awakens in Dimension Z, a realm full of Zola's creations known as mutates. Next to him is a baby floating in some sort of chamber. Cap breaks free, grabs his trusty shield, and leaps from the train. It is soon revealed that he took more than just his shield, he grabbed the baby as well.
Flash forward a year and Steve is seen a grungy mess. With him is the child, now able to talk and walk. To make the hell that is Dimension Z feel slightly more comforting, Rogers has given the child a name; Ian. The situation is hopeless, and Cap is left to question if he did the right thing by putting Ian through such hardships, especially at such a young age. The comic time jumps again, now eleven more years in the future where Ian is a far more capable child.
The pair finds refuge amongst a colony of creatures known as the Phrox, however, this good fortune doesn't last long. Zola finds the colony, and, along with his other child Jet, attacks the settlement. Rogers loses the battle, left for dead as Zola takes back Ian. Just seconds from death, Steve reflects upon his mother, drawing the inspiration he needs to pull through.
Zola quickly brainwashes Ian against Cap, changing his name to Leopold to further distance their connection. As Cap sets off to rescue Ian, he finds himself face to face with Jet. Thinking Rogers killed her brother, Jet attacks with ferocity. Cap's heroic ways catch Jet off guard, inspiring her to turn against Zola herself. Unfortunately, the corruption in Ian, now Leopold, is much deeper, ultimately leading to a heart-wrenching battle between pseudo father and son.
After shooting and stabbing Cap, Leopold holds a gun to Rogers' head. Rogers' tells Leopold that he can go ahead and kill him, he just wants one thing, for the boy to choose his own name. The kid breaks down, choosing Ian. As fast as this positivity is brought about, it is taken away; a gunshot rings and Ian's life fades. Standing there with a gun in hand is Sharon Carter, thinking she finally found and saved Cap.
Steve is distraught as he watches his son be killed by the very woman he loves, but he knows he must carry forward. Carter, Rogers, and Jet all work together to escape Dimension Z. Just as they are about to leave, Carter sacrifices herself, detonating explosives to stop Zola from getting to them.
In the end, a story that sounds ridiculous, Captain America kidnapping a baby and raising it as his own, turned out to be one of the most tragic moments in Steve Rogers' life, costing him both his lover and his child. However, as is the way with comics, it's rare for a character to stay dead forever.
Time passes and Cap finds himself bedridden after suffering a terrible defeat that literally sucked the life out of him. A portal opens, unleashing a slew of Zola's mutates and a mysterious warrior. The warrior seems hellbent on reaching Rogers, evading and taking on numerous other heroes, including the likes of Iron Man and Thor. Upon meeting Rogers, the warrior removes his helmet to reveal, yup, you guessed it, Ian, now a fully grown adult.
He explains that he was healed by one of Zola's bio-mass tanks, and that Sharon, also alive, raised him like a child of her own. Leading the Phrox against Zola's mutates, Ian became known as a fierce soldier of Dimension Z. He has come to find his father in order to get his help in defeating Zola once and for all. Turning back to the situation at hand, Ian and the Avengers then take on a mutate supergroup, the Unvengers. Exactly as their name implies, the group consists of mutate counterparts of respective members of the Avengers team. Eventually, this particular journey ends, but the adventures of Steve Rogers and Arnim Zola's son keep going, and boy do they stay complicated.
Now dawning the moniker Nomad, he teams up with Sam Wilson, the new Captain America. Obviously, as the son of the original super-soldier, not sporting the shield himself strikes quite a chord with Ian. The duo is sent on a mission to save a child from Zemo. They rescue the kid, but in the process, Nomad ends up killing Batroc the Leaper. This causes more tensions between the pair as Wilson argues killing is never the right option, and that actions like that are why he isn't Captain America.
Nomad convinces Wilson to leave with the kid while he holds the remaining villains off. It turns out that the rescued child is a Hydra spy, shooting Wilson and returning to serve Zemo. The battle leads to Ian striking down Zemo fatally, poetically concluding his earlier sentiments about having to sometimes sacrifice life for good. Zemo is an evil mastermind of course, and sets the base in which they are all in to self-destruct.
Ian survives the exploding Hydra hideout by using the Infinity Elevator, only to be lost in the Hydra Empire domain. Confronted by his dimensional doppelganger, Ian ends up losing, having his spine broken. He is saved by a woman named Elle, the daughter of that realm's Steve Rogers and Sharon Carter.
In time he is teamed up with that dimensions Rogers, leader of a resistance against Hydra. The rebellion is attacked by Venom, killing everyone but Ian and Elle. Despite her escape, Elle was still infected by the symbiote.
They come face to face with Zola only for him to try and barter for the regenerative gel found in Ian's suit. Things take a bit of a turn when Zola attempts to use the dead body of Steve Rogers in the discussion, leading to battle.
Using a device made by Tony Stark, Ian is able to capture Zola inside Rogers' corpse. Before being able to completely defeat Zola though, Ian is attacked by Leopold and that dimensions' Hydra Avengers. Ian escapes and returns home, carrying on as Nomad.
Even more ludicrous than it sounds in concept, the story of the baby that Captain America kidnapped from a villain to raise as his own is as unique an origin story as they come.