Xavin came to earth to marry Karolina Dean, but was turned down because she said that she was attracted to females. But Xavin revealed that this was not a problem because Skrull are natural shape shifters, meaning that he could change gender as easily as she could change her clothes. So Karolina left with him to get married. The intricacies of Xavin and Karolina Dean's relationship and the nature of their sexuality together are not completely understood by the Runaways, but appear mostly homosexual.
During the wedding ceremony, one of the Skrulls made a rude comment towards the Majesdanian brides' maids, and this reignites the war between the Skrulls and the Majesdanians. The brawl ends up destroying the planet (no one is expected to have survived other than Karolina and Xavin).
Xavin and Karolina return to Earth and become members of the Runaways.
Xavin was a major part of the plan for rescuing Molly Hayes from Geoffrey Wilder, and foiling Wilder's plan, in which he attempts to sacrifice Nico Minoru (of the Runaways). Wilder was planning to revive his family by giving Nico's soul to the Gibborim.
During the Civil War Xavin's neck was broken by Marvel Boy, and he appeared to be dead. Later, Xavin was able to fix her neck and heal herself.
Xavin, as her betrothed Karolina states, is learning to become more human. Her different, more warlike ideologies sometimes cause conflicts with the other Runaways, particularly Victor due to the later being considered an artificial being. Nevertheless, she is totally dedicated to Karolina, and seems willing to adapt just to be more accepted in the group.
During their time trapped in 1907, Xavin adopts a white male form, recognizing that being white and male in the society they find themselves in will benefit them most.
Upon returning to the present, the Runaways encounter invading Skrulls in New York City. Recognizing the Skrull invaders, Xavin quickly knocks out the other Runaways with a force field and speaks to the invaders. They leave the Runaways with Xavin, who attempts to transport the unconscious Runaways to safety. However, Nico and Victor only feign being knocked out and attack Xavin. Xavin does not fight back and explains that the Skrull invaders are part of an extremist religious sect who believe Earth to be their rightful dominion and view others with superpowers to be sacrilegious. Nico and Victor are convinced by Xavin to run, Xavin telling them that all of their talk of standing and fighting in contrast to the Runaway's motto means nothing when dealing with the invaders, stating that they will not hesitate to even kill young "hatchlings" like Molly. Reluctantly, Victor and Nico leave Xavin behind, taking the others with them in the Leapfrog. Xavin notices the Young Avengers being attacked by Skrulls and manages to save Hulkling from capture. However, Hulkling is injured and both are cornered by Skrulls, who attack them in the sewer system.
As a Skrull Xavin is a natural shape shifter, and can alter her appearance at will. Because of the nature of her relationship with Karolina, Xavin generally takes the form of a black human female. She has also taken the form of a black human male (often when she wants to project a tougher image than what she believes her female form to be) and occasionally a more Skrull-like appearance.
As a Skrull, Xavin can shapeshift to an extent deeper than external appearance, able to rearrange anatomical and internal morphology. Xavin told Mr. Wilder that she didn't fear bullet injuries because she could simply move her internal organs out of the way. Xavin's shapeshifting powers generally take a secondary role to her other powers as a Super-Skrull trainee.
As one of the new Super-Skrull trainees of the Skrull empire, Xavin is also able to manifest the abilities of the Fantastic Four (invisibility and force field projection, stone form with superhuman strength and durability, elasticity, fire projection and control) although not yet to the same degree as the members themselves or the original Super-Skrull, Kl'rt. Xavin states that she can only reliably control her powers if she uses them one at a time. She occasionally shows her lack of experience with the versatility of her abilities, such as trying to stretch from one building to another, rather than creating a relatively simpler force field bridge.
Gender Identity and Relationships
As a Skrull Xavin is a natural shape shifter, and can alter her appearance at will. Because of the nature of her relationship with Karolina, Xavin generally takes the form of a black human female. She has also taken the form of a black human male (often when she wants to project a more intimidating image than what she believes her female form to be) and occasionally a more Skrull-like appearance. Xavin states that changing gender for a Skrull is a simple task, equivalent in meaning to changing one's hair color. Recently Xavin demonstrated that she reverts to her female human form when distressed and unfocused, pleasing Karolina who takes this to mean that Xavin's base gender is female. However, Xavin has secretly expressed some doubt as to whether she is male or female and whether she only changes into a female to please Karolina, who is distant when Xavin is in male form. The only Runaway member who asks Xavin about this is Molly. Molly also informs Xavin of Karolina's discomfort with her male form compared to her female form.
Because of Molly's statement, Xavin shapeshifts as Nico, a form that Karolina already likes, and approaches Karolina. Although Karolina can usually pick up Xavin's scent, Karolina is unaware of the shapeshft, Karolina thinks she is rejecting Nico. When Xavin reveals herself, Karolina reassures Xavin that she is happy being with Xavin as she is.