She made her first appearance during Chris Claremont and Salvador Larocca's stint on the Fantastic Four.

The story of Valeria Richards begins during Sue's (Invisible Woman) second pregnancy. Due to her exposure to the cosmic storm, Sue's pregnancies have always been difficult, as was Franklin's and now Valeria's. Because of her body becoming weakened, Sue gave birth to a still-born daughter. (The trauma of losing her daughter would eventually trigger her transformation into Malice.)

In reality, using his vast psionic abilities, after feeling a part of himself missing, and guided by Roma a guardian of the Omniverse, Franklin Richards, went back in time and managed to save his sister's life before she was born into the world, as a still-born. He sent her "some place else" and for years both Reed and Sue believed their daughter to be dead.

A few years down the line, a girl appeared out of nowhere at Pier 4, during the Fantastic Four stay at the location. After returning from the Heroes Reborn Earth. Everyone, naturally, is weary of this new girl but Valeria remains optimistic. Franklin is one of the first to accept and believe in her story, creating a very strong sibling bond, although in this reality she is the older sibling, while Franklin is the younger.

During the course of her stay we come to find out that in her reality she was the daughter of Victor Von Doom and Baroness Susan Von Doom, which caused a large rift between mother and daughter.

Susan believed that Valeria was lying, and was a part of one of Doom's ploys to get back at the team. At the same time, she refused to accept the possibility of marrying Victor one day, and since Valeria is assumed to be the a result of that union she must in turned be denied. Reed decided to make a few tests to see if what Valeria spoke of was true but Susan didn't want any of it, and went as far as calling her daughter a "monster".

Valeria overhearing her mother's harsh words runs away, only to find herself in a dangerous situation involving a mind controlled She-Hulk, Absorbing Man, and Titania, the Thing eventually joining the small gathering. She manages to fend them off long enough for the Fantastic Four to come to her aid. Sue valiantly fights all four Super strength brutes, and accepts Valeria's as a friend and invites her to stay with the FF at Pier 4.

Valeria and Franklin's relationship only grows during this time. Valeria remains with the Fantastic Four for the majority of her stay in that reality. Even meeting Doom along the way trying to get her "fathers" attention but Doom would have none of it.

A strange phenomenon is soon felt to the gang and they soon learn that the Heroes Reborn Earth is trying to merge with the regular Marvel Earth, and as a means to save both Valeria and Franklin, Sue commissions a ship to send the siblings away in. Both she and Franklin eventually find themselves on the other side of the universe at a school for the gifted. There she learns from Franklin about Roman, a woman who he'd seen in her dreams and was helping him rectify what was about to happen. This was around the same time that the head of a Galactus from an alternate reality appears in New York. Franklin and Val eventually return and find themselves thrust into a confrontation that would determine the fate of more than one world.

Upon returning, the truth about Galactus' and Abraxas existence is revealed. Galactus exists to keep the Abraxas of each reality prisoner. Unfortunately, because the Galactus of an alternate reality was already killed Abraxas was free and able to cause mayhem. As the Fantastic Four travel from dimension to dimension trying to find pieces of the Ultimate Nullifier, Valeria helps in anyway she can. After all the pieces of the nullifier are found the FF find it useless, and soon find that they were betrayed by a member of their group. The situation seems dire and then something happens which awakens Valeria and Sue to the truth. Both mother and daughter share visions of Franklin and what he did in order to save Valeria's life, and finally Sue accepts Valeria as her daughter after learning the truth.

Seeing that Abraxas was hard to defeat, eventually Franklin and Valeria combine their powers to restore Galactus to life, realizing that Galactus was in the heart of Eternity. In the process of that plan of attack, Valeria's life is forfeit. Or was it? Moments after the event, Sue is shown calling out to Franklin and carrying a rather large bulge.

Valeria's life once again returned to that of a baby, and inside her mother's womb, making Sue once again pregnant with the baby girl she thought she lost many years ago and also the truth of Val's father was revealed. Her father was Reed Richards (Mr. Fantastic) and not Doctor Doom. And this was a gift bestowed upon the team as a thanks for saving the worlds from possible annihilation.

When it came time for Sue's pregnancy to come to term, she found herself in a difficult position. Her body was once again weakening, just as it had the first time. Johnny Storm (Human Torch) sought Dr. Doom' help since Reed was unavailable due to an encounter with the Hidden Ones and trying to avert a crisis.

Surprisingly, Doom agreed to deliver the child on the condition that he be able to name her, and Sue realizing both her life and that of her child was in danger, agreed on the terms, although she'd been very reluctant. Doom managed to deliver the baby girl safely using both science and magic and he named her Valeria after an old love. But unbeknownst to Sue or Reed, he also placed a spell on the child, thus making her his magical familiar. Which would later result in the Fantastic Four living through one of their worst ordeals.

About two years later, Doom takes advantage of the spell he cast on the child, and thus carried out a surprise attack on the Fantastic Four. In the course of it, Franklin was kidnapped by demons and sent to Hell. And Valeria is heard uttering her first word, which was "Doom". The gang went after Doom to "cure" Valeria and find their son. Unfortunately, it was to no avail, Doom's magic was too powerful and he took Valeria while the Fantastic Four suffered an ordeal of living painful versions of their teammates powers.

Eventually, with the help of the astral projection of,Doctor Strange, Reed was able to free himself, his teammates and they managed to rescue Franklin and Valeria. At the same time, freeing her completely from Doom's grasp and ending her bond with him as his magical familiar.

At the moment, Valeria is living as normally as one can live with world-famous super parents and family members, acting like many other child red of her age.

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Powers (Valeria Von Doom a.k.a. Marvel Girl):

Force-field generation much like her mother, which means she has the potential for an unlimited power source. Her only only limits are her own imaginations and reservations.

Time manipulation via a "Time Dance".

Able to transform into an armored state, whose armor is similar to Dooms.

Genius level intellect on par with Reed Richards (her biological father).

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Powers (After reverting back to a child):

None, but it should be noted that she's still a child, and might not exhibit her powers until she hits puberty like most mutants.

In Marvel Knights 4, Johnny encountered a "future" version of Valeria who had an advance form of her mothers invisibility power. Using her powers she was able to truly make a person invisible hiding the persons kinetic energy, heat energy, etc.